Just my $.02....which might not actually be worth that much!
As for the GPA, mine was 2.06 when I first did Peace Corps, so that won't actually stop you from PC itself (and I've been invited three times now); that being said, there were a couple of sectors with GPA requirements (I'm not sure if they still have them, as requirements are set by the host country), mainly upper-level education positions.
In my experience, my experience has been more of the focus than the GPA. I honestly can't remember if I was asked to explain my low GPA, but I don't believe so.
As far as hindering your chances of getting in, that probably depends competely on the rest of the applicant pool for whatever position you get put under consideration for. Like I said before, it is not in and of itself something to worry about too much.
The application process can take up to a year...it really is different for eveyone, but the sooner you apply the less spots they'll have filled. If you wait until the very last apply-by date, you might find that some of the slots are already taken, and you will be competing for many less positions. Personally, I always say apply as early as you can.
Right now I believe the PC website has positions up through September 2016 posted, and it looks like there's a number of them in the July-September timeframe. If that works for you, I'd start applying NOW.