Ants!!!!

I really should not complain too much because in other homes we have had cats/kittens dropped off and take up residence in the crawl space (in 2 houses) and we have had mice in a couple of houses we lived in the past. So far in the 3 years we have been here there have been no stray animals (Chris would beg to differ on Tebow) and no furry little creatures scampering in and out of walls. Instead we have ants, many ants.

Our problem started last summer while I spent 3 weeks at the lake and Chris was gone to World Changers. I happened to come back to Raleigh one day and decided to stop in and check on the house before heading back to Lake Gaston. Upon entering the house I saw a thin black line on the living room carpet. Upon further inspection we realized it was ants coming from the back door across the living room, into the master bedroom and under the dresser and up to the window sill. I stayed for 2 hours spraying and vaccumming up ants. We continued to have little infestations throughout the past year either at the side entrance by the kitchen or at the back door again. We would spray, suck em up, spray some more, etc...

We have also tried grits (found that on the internet) and that seemed to work until last weekend.
Chris went out to do yardwork and when he opened the storage room there were ant hills all around the inside of the room and when he ran the weedeater they had gotten into some mulch in the back yard and made homes in there. Now we have several huge mounds in the yard.

No matter what we use on them they keep coming back and just won't DIE!!! If anyone has any suggestions of how to rid our lives of these little pests please let us know. My feet got eaten up tonight while I was trying to sprinkle yet another ant killer on them and Idon't think my feet can take it anymore...please help!