For starters, my frank personal opinion and pastoral advice to you is that the ELCA is not a good church for any Christian family. As a denomination, they have for a long period of time moved away from Scriptural truth. Of course, within every denomination, you may have individual local churches and their pastors that have remained faithful. But when one supports a local ELCA, they are also supporting the work of the broader denomination in its unbiblical practices. In my opinion, between the ELCA and the LCMS, the LCMS is a much more viable option - hands down.
Now, the second part of your question concerns similarities and differences between Lutheran and Reformed. Such a discussion would require a treatment far beyond the limits of this e-mail (and even my own personal knowledge!). However, I will highlight some major points below. Before I do that, I would simply point you to one resource I know which does comprehensively compare the two systems. If you like reading a lot, you will like this book. Louis Berkhof's Systematic Theology is where I learned the differences between the various systems of theology. I do not personally know of any other resources that are as comprehensive.
That said, lets begin with the similarities between Lutheran and Reformed:
1. Emphasis on the "solas". Both Reformed and Lutheran affirm that Scripture is the Christian's authority alone, that a person is justified by grace alone, through faith alone, because of Christ alone, and all to the Glory of God alone.
2. Both believe in the baptism of infants.
3. Both maintain a high view of the church (at least higher than what is held by the general evangelicalism that is so popular today in America).
OK, now for some differences:
1. The Lord's Supper. Lutherans generally believe that somehow Christ is bodily present at the sacrament, a view often times referred to as "consubstantiation," alhhough I have heard some Lutherans reject that term. The Reformed, on the other hand, believe that Christ is present at the Supper by his Spirit (and is not bodily present). This means that that the Supper is more than just a memorial and a real means of grace (for those who receive the Supper by faith, God strengthens them spiritually). While Christ is not bodily present, there is a "Real Presence" in that He is present spiritually.
2. Baptism. I have understood that the general Lutheran view of baptism is regenerational. In other words, by the administration of the sacrament a person is regenerated and made to be "born again". The Reformed, however, believe that, certainly, God is able to regenerate a person at baptism, but He does not necessarily do so.
In other words, God is not so restricted that He must regenerate a person at baptism. He may regenerate a person whenever He wants - before, during, or after baptism. Of course, another option is that God may decide not to regenerate a person at all! The Holy Spirit is sovereign, and like the wind, He may blow when and where he pleases (see John 3).
3. The Law/Gospel distinction. Lutheranism tends to draw a very distinct and pronounced divide between Law and Gospel (as well as between Old Testament and New Testament). The Law is generally seen as an oppressive thing by Luther. The Law, for him, only seems to have one primary purpose; i.e., to act as a schoolmaster to lead a sinner to Christ, faith, and repentance.
The Reformed, while affirming fully this purpose of the law, also teach other uses of the law. For instance, the Law is a guide even for the unbeliever. Luther seems to dismiss this use of the law. He also seems to believe that since the Christian is free from the law for his justification, somehow he is also free from the law for his sanctification.
Calvin believed that the Law was a way in which God administers his common grace, using the law to suppress wickedness even among pagan peoples, and also promoting righteousness and social orderliness. And for Calvin the third use of the law is the "principal use, which pertains more closely to the proper purpose of the law [and] finds its place among believers in whose 'hearts the 'Spirit of God already lives and reigns" (Calvin's Institutes, II. vii. 12). This is in keeping with the Psalmist's statements, "I find my delight in your commandments, which I love" (Psalm 119:47, English Standard Version) and "Oh how I love your law! It is my meditation all the day" (Psalm 119:97, ESV), and with the Apostle Paul's statement, "I delight in the law of God, in my inner being" (Romans 7:22, ESV).
So, to summarize this point, for Luther the covenant God make with man seems to be completely one way. God makes covenant with man to save him and that's it. The covenant has no stipulations for man, whereas in Calvin's view of the covenant, it is a two-way street. Yes, God sovereignly administers his covenant to his people by grace alone, but every covenant has obligations. Every covenant has, in other words, Law AND Gospel. So the Reformed tend not to separate Law and Gospel as dramatically as do the Lutherans.
There is more we can go into, but I'll end it here. Again, I think you'll find Berkhof to be an indispensable resource for this. He not only gives you the Lutheran view and how it differs from the Reformed on various points of doctrine, but he does the same for Roman Catholicism and Arminianism as well.