Bed bugs, Help!!!!!!!!?

ok, here is my situation, We adopted a USED couch, when we got it in the house i noticed 2 little bugs in one of the seams when i was disinfecting it, i had not a clue what they were but when i did alittle research online i can across bedbugs, and much to my surprise they matched the description to the T of the little buggers that i found!! I bought lice spray, vaccuumed the couch to the extream and bought a pesticide for indoor use and sprayed all the cracks and crevices of the couch, I was positive they were gone, but once again after not seeing them for 2 months, my fiance' found one on the couch again!! so i searched up and down in every room, and found ONE on the ceiling in my bedroom, i tore everything apart, vaccuumed againg and sprayed the pesticide in all the baseboards!..washed my sheets ect. finally..my question is..what else can i doooo!! to asure these freaks are gone!!! Im going to borrow a steamer from a friend and steam everything humanly possible,im positive i only have a mild infestation but i want to catch it before it gets worse!! what else can i do! im freakin' out here!! HELP!