When I was learning to pray, a very kind sister made me a set of cards that had a line in arabic, followed by the meaning in english. As I prayed, I would read the arabic alloud, and then read the english to myself in my head. That way I would know what I was saying, and it greatly helped to make my salat have more meaning.
I made copies of those cards that you can download here -
http://www.mybloop.com/rahma/Islam/salat.doc
And yes, it's ok to use those two surahs while you learn others. I only knew ikhlas for the longest time and would use it over and over and over again.