L&L marine should have what you need as far as new trim.
800 969 7278 They're in OC.

Always start to hang the trim at the transom using one piece and wraping it around the either side of the boat going forward so you don't have an unsightly seam in the middle at the rear. If the transom has any crown to it starting here will allow you to work the piece to that crown givin it a nice look. Trying to trim down the length of the boat and then butting both pieces in the middle of the transom is tough (if there's crown) if no crowns there, then it's cake. Do the same at the bow, then fill in the remaining gaps, taking time to stand back and make sure the trim is true. Never follow the seam of the boat to center the trim on, the guy that ground the pieces when the boat came out of the mold may have ground a little to much here or there.

If you're using trim with the rubber insert, rivets will work fine, if you're using the old school half dome trim, use SS screws but don't over tighten because you can dimple the sides of the boat, pulling the glass in (out) towards the trim.

I have the world's greatest air rivet gun here if you need to borrow it. Had it since 1974 and still have never seen on that works better.