Frontsite or Gunsite will serve you well, believe me it is worth the money.
I've also taken a few courses in addition to the ten or so at the above from Sig Academy. A pal of mine Tim Connell, a Police cheif in Virginia comes up here to Canada and teaches at our school for SigArms (we are one of Sig's distributors). 400$ may sound high, but guys up here are paying 3 times that to take courses, and we can't even get CCW permits to take advantage of the training, so count yourself fortunate and take a course as soon as it is convenient.
You'll have a blast, and learn a ton of stuff you would think you would have already known, but you didn't.