continuing slow 3G

I've had my HTC Desire with Cellular South since October 2010. It wasn't until around January when i noticed my internet browsing had slowed down considerably. Also i listen to Pandora Radio all the time. Where used to it would play constantly non stop, now it buffers like 10 times during a single song. I've tried resolving it with Cellular South but they don't know whats wrong. They only tell me to pull out my battery and turn it back on. There is no telling how many times I've done that. Theres really is no point in having data if its going to be this slow. I used to get around 800kbs now it doesnt break 400kbs. Can Anyone tell me whats going on???

Here is a current speed test.

My brother's Hero just got 904kbs download and 774kbs upload on the same carrier both of us with full coverage.
Here is my brother's Speed test: