if you want to keep the same tires, just go to
www.car-parts.com select your make and model and look for 15'' OEM wheel set. usuall they comes with no hubcaps so reuse yours as they look good
that's probably the cheapest option, but ... you never know exact wheel condition before ordering, so either going to place you find listed or calling them up ahead would be recommended. consider only listings on a full set (cheapest option) and quality grade A only, check descriptions too for more details, sometime they put them other times they don't.
other than that, craigslist or ebay (often reconditioned wheels, looking like new) offer some good deals on oem wheels, just make sure you know exactly it comes off the same (or similar) car with the same bolt pattern.
if you are willing to swap the tires for something else (much more expensive this way), maybe get oem 16'' wheels and matching 205/60/R16 (or other options that fit the rim)?
you know you could always get a set of TRD 18'' rims hehe, but that costs a bomb.
EDIT:
which model of Bridgestone Potenza are you using? I had those (G009 I think) on wife's 5s-fe with exact same wheels as yours and they were useless especially in Winter after 2-3 years, had to replace them regardless of leftover threadlife left.