I got a set of 205/60r16 Firestone winterforce tires from tirerack for just under $320 to my door. I'm sure they're gonna be noisy on the road, but I think they'll get me home.
I suspect the TPMS will only recognize one set of sensors at a time. Assuming that is the case, if you get an extra set of wheels you'll either need to swap the original sensors over or go back to the dealer to have the sensor serial numbers changed in the cars computer in the spring and fall.
Swapping the sensors isn't too bad. It can be done by just breaking down the front/outside bead; no need to dismount or rebalance.
Based on the tire size, it sounds like you got the SI. How ya like it?