Can I make my bootcamp partition bigger without formatting it? Is it possible to increase the size of my Windows partition without having to wipe the entire thing?
Not with the built in tools. Moving the start of a partition is no trivial task. Resizing your main Mac partition only grows/shrinks it, but because your bootcamp partition resides further on your disk, it needs to be moved up before it can be grown. This is not a trivial operation and is not supported out of the box in either OS X or Windows.

You will need a specialised 3rd party tool like iPartition, but use with care and triple check compatibility.