I've seen this before, was helping out another mywireless user, he also ended up on the 10.x range on most connects, and could only ping sentech.co.za, when he did get a valid IP, only page headers were downloaded, the fix was Dr.TCP, and all was good since then.
The funny thing is that I don't see MTU packet sizes causing cooked ip allocation, so it was probably a co-incidence that both problems fixed the day I dr. TCP'd the system.
Give it a shot, theres nothing to loose,
as google say, "I'm feeling lucky"
interesting trick : Type "weapons of mass destruction" in goolge and hit the "I'm feeling lucky" search, read the error message carefully, its a good laugh!