First off, you need to build your arena more/raise the prices.
Your arena and pricing should look like this:
Bleachers : 5000 (Current Price: $7) (Price as of 11/5/2011: $8)
Lower Tier : 450 (Current Price: $40) (Price as of 11/5/2011: $40)
Courtside Seats : 110 (Current Price: $130) (Price as of 11/5/2011: $120)
Luxury Boxes : 5 (Current Price: $800) (Price as of 11/5/2011: $800)
Depending on your record you may need to build or lower the prices. Your extra revenue will help you afford better players.
It looks like you should train big men. Big men traineestend to have bigger salaries than guard trainees. If you decide to train big men then sell your young guards and then buy older players who have been trained. Also, OD is the most important skill for a guard, so make sure whoever you buy has at least prolific OD.
Hope this helps. If you have any more questions feel free to BB-mail me, or post here.