Yeah check your firewall (if you can) see what other programs are accessing the internet at the same time as your game and try to close a few of them. Also if you can see a server browser try to only connect to servers in your own country that should insure a decent ping. Other than that it's a quick email to your ISP and explain your problem but I doubt they'll be able to do too much.
Oh yeah and if you're in a household where other people can also access the net while you're on............KICK THEM OFF !
some quick tips...
get tuneup utilitys 2012. use its internet optomizer to match your router/modems settings to your line speed... it doesnt have to be absolutely accurate just withing a few mb...if you have a 5 mb line then select the 4 mb settings. if you have an 9 mb line then pick the 6mb settings as there pretty much identical for the none expert user.
its actualy best not to select settings that are faster than your line speed. and by that i mean your actual line speed not the advertised speed.
other things you can do... connect directly to the modem form your ethernet via a cable. if your on a home network put your pc at the top of the connections list. never use wirless and turn qos packet sheduler off via the gpedit.msc in the run command box on start menu... you will find it under reserved bandwidth just click enable and reduce the 20 down to 0. click apply then click dissable. (dont set it to not configured or it wont work)