I believe that all propellent cans are the same size. What you need is the attachment from Paasche to adapt the hose to the can and you should be able to get from the same location you got your A/B. Here is a pic of it.
Depending on how much you are going to use your A/B, you are probably going to quickly find that the propellent cans are a costly venture. If you can afford it, get yourself a compressor, you'll save money in the long run.
Happy Modelling and God Bless
Robert