Structuredoc has given a couple of good tips to help with some of the issues.
Asking about adding 15MPH of velo in a relatively short time is asking to do something most guys are never able to do. I am not saying that to discourage you, just the opposite. I don't know if you can pitch 90, no one does really, but letting answers saying there is work to be done effect motivation is concerning. The bad news and the good news is the same....there is work to do. But there has to be a realistic approach. Set smaller goals on the road to major change. Maximizing conditioning, getting on a structured throwing program, implementing mechanical changes ect. Motivation with such a goal can only come from within oneself.