You will get upto about 70 mill including tv rights if you win the EPL, but that would include stadium income. FAcup and League cup only bring in nominal amounts, even if you win them, but every little helps.
Thunderstruck has a point about bonuses, keep a close eye on them in contract negotiations, i once ignored them and ended up paying far too much in bonuses.
Loan debt is down to the board, they may restructure the debt in better financial situations, but theres nothing you can do to encourage this.
If you go into boardroom, under Budjet Adjustments (top right section of the screen below the top menu), hit edit budgets, and take the slider to the far left. This well remove your remaining transfer budget and increase your wage budget, and increase interest payments to your club.