Once you leave the US it's going to be tough getting back in on anything other than a student visa.
If you are in the US, don't leave. Find a job if you can (and as a foreigner right now, it's next to impossible) and stay here as long as you can. That alone can take you anywhere between five to eight years. Also, during that time, travel out of the US will always be risky. Any Customs and Borders agent can revoke your Green Card upon re-entry if they deem that you are no longer a permanent resident and they could do it because you get into an argument with them.
So in short, if I were you, I'd stay in the US. And don't travel abroad while you're awaiting your Green Card as well. The paperpushers here have this nagging habit of resetting your "time in country" to zero every time you leave.