Yeah I just saw an ad on craigslist, for people who had flashed their android phones, that he would fix the mms and internet problem for $10. So, apparently their is some kind of flashing process you could probably find yourself either here on this board or around the internet and fix it yourself. If I come across it, I'll post it for ya.
Also, I wanted to make sure that your aware Metro PCS doesn't even have 3G. So it'll be slow going internet wise.