I completed migration assistant but it created a second user login and didnt transfer to my existing login?

I bought a mav book pro and it had an administator login from the store and i had set up bookmarks and installed microsoft office for mac. A few days later I completed the migration assistant to move my pictures, documents and Itunes to my new Mac. After completeing the transfer and restarting the Mac I know have 2 seperate logins. The original from when I bought it with microsoft office installed and now a second one also with my Name but the password is my tunes password. I went into the second login and my Itunes tranfered fine with my documents but this login is has none of my apps or bookmarks I set up with the initial login when I bought the Mac.

Why didn't the Migration Assistant transfer into my existing login where I had installed microsoft office for mac? Can this be fixed? I only want one login. I would be ok with the new login thats has all my documents and itunes can I merge them or move the login with Office for Mac into the new login or the other way around? Can my Itunes be switched to the original administrator login. Document are easy I can open them from a memory stick.