The F27 isn't hurting you nearly as bad as the 15-seat Beechcrafts. You are also too spread out with your destinations. You shouldn't open routes to new destinations until you max out the potential for existing ones. For example, you could have another 2 flights/day to ORD, 1 more flight/day to LAS, LAX, and ATL. By not maxing those out first, you're spending unneeded money on extra marketing and staff.
My advice would be start over--you have 3 fleet types and only 10 planes. Even before the F27, you had 2 fleet types with 9 planes with one of those fleets being 15-seaters. You're not setting yourself up for success by doing this.