Hacked Website?

Help!! I’m somewhat new to WordPress and am stumped. Someone has apparently hacked my site to include links to advertisements, etc. and I cannot remove them. Please have a look at a page on my site and note the links for the words “application” and “register”–as examples. Can someone tell me how to get rid of this stuff? And how to protect my site from it happening again? Please see http://www.taxcompliant.net/site/integration/

Thanks very much. Clark