With your current bike; are the gears working properly? The description you're stating; makes it sound like you're
in a high gear. So; before buying another bike - make sure the gears are mechanically okay and that you're using
them properly. Where are you in NYC; I can give it a quick look. No charge of course.

If after checking the gears and you still want to get another bike; check out Recycle a Bicycle. It's a non profit
organization that sells/builds used bikes. Unlike some shops that sell riders incorrect sized bikes just to make a sale;
RAB's reason for existence is to get folks on bikes. They will sell/build a bike that's right for your riding style and size.
Hope this helps, keep us posted.

Shops | Recycle-A-Bicycle