Hard to beat
www.performancebike.com for prices. Doesn't help if you need to try out a saddle, though. But for the other upgrades you mentioned, something to think about. I agree you need to use the "search" function on here for some input on prepping for your first century. You'll definitely need to gear up your riding to being able to do at least 70 miles comfortably before attempting a century. You have a decent timeline available. Now you need to develop a realistic training plan to get you there. Good luck. You should have no problem if you follow a basic training schedule.