To be honest mate. I've had a look at your arena and you keep selling out (so your not getting as much money as you deserve). You have the money, so insead of raising ticket prices, expand your arena appropraitly. (look at the best teams in your division). That may cost $300,000 + The rest, well increase your scouting to about $20,000/week if you think you'll go down so you can get a really top draft pick.
Also, make sure you have good quality trainees as that's where you'll increase the quality of your team (or the size of your wallet). I got mine (and im a Div II team) for about $200k - $300 k each so you could find one to suit.
So yeah, arena, scouting, and make sure your training's not going to waste. That's what i'd do. But im also one of those guys that trains just for my team and dont sell on the whole (against the advice of most of the top players).
Btw, you really dont need to be wasting money on a lvl 4 doctor at the moment. That's really just a luxury. I'd go lvl4/5 trainer, lvl 3 PR, lvl 1/2 Doctor. Spending less, getting more fans. But that's only worth it if you expand the arena.
Good luck.