I've had the same problem you're having, and it's real pain no matter what. The stuff you bought originally is probably your best bet, even though you will not see immediate results. You have to either 1)locate the queen or 2)slowly poison her through her workers. The brand I used was Terro, but any sugar water slow poison will probably work. You have to be patient, even 2 weeks to a month is not out of the question, but it's the only way to completely destroy them.

A couple of tips:
Find their point of entry, and place ample poison there to discourage them from exploring the rest of your home, try to avoid killing them off with sprays so they keep delivering the poison to their queen, and make sure you keep the poison readily available, they'll eat a lot more than you'd think.