If you are using a router there may be a firewall in it 40KB/s would be about max for most DSL connections you can do a speed test at the link below. If LimeWire is able to search and others are able to download from you I would not worry about it.
http://www.speakeasy.net/speedtest/ U.S.
http://specials.zdnet.co.uk/misc/ban...eedtest50.html U.K.