W902: UK phone in US, no 3G service

I have a w902 from the UK, i would like to use the 3G here in the US.
I understand that the phone is set to UMTS 2100MHz for 3G right now and i was wondering if i could change that to whatever ATT uses here in the US, i believe it's 850MHz or 1900MHz.

I've noticed other people with similar issues but i couldn't figure out a solution, the responses where vague or it seemed like just gibberish.

I would hope it's a simple patch but I'm willing to do whatever.

This is a challenge I hope some one can pull off, it would be awesome.