go here, make sure you have java enabled under ie6, and click the start button. don't do anything while the test is running (make sure you do not have any traffic while running the test).
after it's done the first red bar tells you your download speed while the second red bar tells you your upload speed. remember that those numbers are in bits, so to get bytes just divide the number by 8.
if the numbers you get confirm/match your current speed, then i'm sorry to say that's your max ul speed and there's not much you can do unless you can cough up some more dough for your isp
btw, what's your connection anyways? cable, dsl? if it's dial up, then umm, don't even bother, lol