I have bats around my house also and did a lot research one summer (last summer was it when got warm way to early?) about mosquito prevention. Bats, while commonly suggested won't help that much as only certain types will eat them and mosquitoes alone make up a very small part of their diet.
Most of what I read that made sense was to get rid of any standing water. Even the tiniest amounts can be a breeding ground. I have koi pond and I could see all the larva in it even with good water flow. I did add some smaller fish (ruby red minnows) but what made a big difference was a product called mosquito dunks. You toss a small puck in and it dissolves, the larva eat it and die. Completely safe for fish and other animals...never lost a pond fish from using it.