Of course you can fill your bottle from a compressor..only problem is, teh compressor.
Firstly, it has to be teh type that provides breathing quality air.
Secondly, it has to be able to supply to 3000 or 4500 psi. These compressors are expensive...like £000 expensive...Bauer make them.
Also...dive tanks filled at dive shops can either be cheap, or well expensive...DO NOT MNETION, that it is for anything other than Scuba...learn a few buzz words and say you are training with a mate...or whatever...my local dive shop charges double (£10) to fill a dive tank for non scuba use (read as airguns)...apparently to do with insurance...but that is just bollox.