D.K.
Libraries are a great place to visit, especially during the winter! You don't have to go during story time. All the libraries with children's rooms that we have visited have fun, age-appropriate toys, and of course lots of books! Don't count them out just because the class schedule doesn't meet your needs.
When my twins were little, we also went to the mall a lot. Just as another free, climate-controlled place to go. We would go to the pet store & say hi to the animals, go to the book store or toy store... (mostly because I have an older daughter too, that wanted to got to those stores!) Babies are just happy to have a change of scenery. And it only has to cost a lot of money if you let it! :)