question about swapping wheels

[hissatsu]

i just took off my steelies and put on tc stock rims and tires. The tire pressure light stays on whenever im driving. Should i replace the tc stockies' tpms valves with my steelie's valves? Also, if i were to buy new tires for the 17 inch tc rims, what would be the best size to keep the mileage, mpg, mph, etc as close as possible to what it should be? Thanks a lot!!