Bugs entering through window. How to keep them out/kill them?

I put an air conditioner in my window, and shortly after starting finding some bugs in my room. Several were spiders and several looked like quite large ants. I bought some foam stripping to stuff around the air conditioner and in that gap between the window panes, but I'm still finding bugs. Is there a multi-purpose pesticide I can spray or leave by the air conditioner that will kill them before they get into the apartment? I know there are ant poisons and whatnot, but it's more than one type of bug, and honestly I'm not entirely sure if they're actually ants since I freak out and smash them to bits the moment I see them. I really loathe bugs and don't like finding them in my bed, so suggestions would be really appreciated.