jdh - congrats! My wife recently bought me the same brush, you;ll like it.
Any hobby type popellant will work, you'll just have to buy and appropriate adapter to be able to screw it to the 1/4" couping at the end of the airhose, I am sure www.dixieart.com has one on their site somewhere.
As far as being ok, it will work for you, but spraying with a propel can and a compressor are somewhat different. At first they act exactly the same but as you spray, the can will get cold and the pressure will drop. So you will have a tapering pressure which will cause a few problems but if you let it warm back up it will go back to spraying full pressure.
Badger, Testors and a few other companies make the cans and I **think** they are all the same fitting on top (better check first) and as I said earlier, you will need some type of adaptor that screws onto the top of the can that can also connect to the airhose.
I wouldn't waste too much money on the propel as it is rather expensive... anywhere from $7 to $10 a can.. 6 cans could buy you a hardware store compressor that would work for modeling just fine as well as practice. (And run a nail gun to build your wife a nice deck to thank her for buying you that airbrush!
)