I'll post the same thing here as I did in another welcome/AR thread.
As for the AR, try gunbroker.com and gunsamerica.com, but be prepared to pay. At this point everyone is basically sold out so you're purchasing what amounts to private stock, but the their only going to let it go, and thus possibly deprive them of it's use forever if a ban is imposed, for a pretty penny. I wouldn't count on the backorder working out in 2013 as everyone has stacked those so deep that it's unlike that you will get one any time soon.
Only you can decide if it is worth it, but if you pay $2-3k for an AR and they ban them, you'll be glad you did. If you pay $2-3k for an AR and they don't, you paid a lot of money to get one now vice in a year. Make your choices and pay your money...if the future were certain either way, ARs would either be going for much, much more than they already are or there wouldn't be a shortage at all.