Bedbugs: our worst nightmare?

I moved into an apartment building four days ago with my boyfriend. We were both living with our respective parents our whole livesbefore we made this move. This morning my boyfriend woke up and saw a bed bug crawling on the carpet. I am positive it was one. We barely moved anything into the apartment, just his twin mattress that we were going to throw out anyway, and all of our clothes, along with a couple bags of our random stuff (no dressers or other furniture yet). He flushed it down the toilet so it wouldn't lay eggs and he called the landlord. Landlord said he wouldn't do anything unless we had proof, meaning catching one. He said however, if we want to move out he will give us all of our money back and tear up the lease. When we first got to the apartment the floors were and still are filthy. The carpets are horribly damaged, and I doubt the previous residents cleaned the whole time they lived here. We haven't been bitten yet as far as we can tell, but please, any advice or any comment at all would be so greatly appreciated. We are desperate.