I have the same problem. I bought the Mobile Me and was then encouraged to set up my iTunes account using my new @me.com address. Not something I woud have done if I had known my previous info would not travel with me!
Like you I could not do the updating so I deleted the Apps that needed updating - BIG mistake. Now when I try to reload I am told there are "no matches."
I have asked, by phone to an Apple Store, if one of the Geniuses would help, but after 2 phone calls, using told to go to the online help store, and because my iPhone is more than 3 months old there is no free help. I have an appointment by phone to communicate with someone. So frustrating, isn't it?
When I get this sorted out I'll get back to you.