Hey you must make sure that you have enough sources (to do this you must see in limewire when downloading from how many hosts eg downloading from 7 hosts will be good speed)
and if you have a router just tell me the name of your router
If you want to know if your ISP limit the speed just go and ask them (call them or email them)
Do portforwarding if you have a router
SET Limewire To default setting To do this Go To:
Tools>Option
Click on Restore Default button