Yes, the only solution is going to be an AP with a wired connection. If you want to use one of your freebies you'll have to upload the modified software as above, either that or buy a new AP which can be used as a stand alone AP.
I have no experience of controller based wifi setups, I've just spent a few minutes looking on the Cisco website and I'd say your probably be better off steering clear on the basis of cost alone. Although there are a variety of controllers av...
Unfortunately, the "C" in CAP16021 means that these access points are designed to work with a dedicated Controller. Unless you are prepared to follow the instructions in this post, below, you wont be able to use them.