Roaches and dead animals in a house I just started renting... what are my rights?

We signed the lease on wednesday and started moving in saturday... once we had gotten enough boxes in the house we started to settle in... only to find that there were 2 dead squirrels in the fireplace and the house has dead and alive roaches everywhere... all the sinks are leaking and on the side of the house there is a ton of water(maybe a busted pipe or something... I dono)... I feel like I have been taken advantage of and do not want to live under these terms... but I have also already paid the first and last months rent plus the application fee and cant afford to put another deposit down on another house... what can I do?...