Kid you may not get laughed at but I may. My son does the Q&A on the Avengers that are returned to BE, and the ones that don't make it out of the shop to begin with. He is doing all the pressure test with 4500 HPA tanks. So to answer your question yes it will work with HPA. It isn't a Low Pressure marker though. But a 3000 psi screw in will work, it will give you the same out put pressure your CO2 was giving you. And you can pick up a steel one for about $120US although I perfer fiber wrap which you can find for around $150 to $170US. I haven 't seen a 4500psi any cheaper than $260 for a screw in. Hope that helps.
Save up some cash. Buy a good gun. ( BE guns are fine to start with but, ya' wanna upgrade soon. ) Then perhaps, buy the new marker. (Perhaps a Spyder?) 
