I need to buy a new bike. My current bike is amazing, but after a bike fit and tight shoulders it's clear that the length between the seat and my handlebars is not long enough. It didn't used to bother me as long as I was riding more upright which for slower rides is actually still very nice.
I'm wondering, how do I figure out the frame size/specs I need?

The other issue is I'm a solid 12 - 14mph rider. I can hold onto 15 on a very flat flat. This pace is fine by me, but as another rider posted, there aren't a lot of riders in the 12 - 15 range. Most are either slower (and beginners) or faster. So I'm thinking about getting a faster bike as well, so that I can ride in the 14 - 17 range.
I really prefer to ride with groups so this is actually a big issue for me. Is this reasonable?

My current bike is an 8 year old OCR1 Giant.

Thanks for your thoughts.