We have had our fair share of ants. Looks like we have got rid of most of them now, inside and outside of our house. Used borax and sugar mix to get rid of the them.
Tried that a number of times... unfortunately my wife doesn't believe it works - she's out there with the bloody spray every time she sees the army marching ...
Soon as the queen is dead then the whole colony dies too, they might be several colony's in the garden.