What should the average download speed be.

I use LimeWire PRO 4.9.11 on a fairly fast laptop connected through a router to a Cable modem (Comcast). Generally my download speeds are 25-50kbs, sometime reaching 100 or slightly over.
When I download stuff directly from the internet it is usually at least 300kbs, sometimes as high as 500kbs. I realize that LimeWire is p2p so it won't be quite that fast, but I am wondering if it should be faster than it is.

On another note, I am unable to use LimeWire when connected to the network at my school, Bates, they block all p2p applications from connecting. Is there any tricky, not necessarily following the rules, way that I can connect, maybe some way to fool the network?

Thanks,
-Matt