have you talked to your bank about getting a student loan?
Some banks will offer loans to help cover your costs while at uni, and may be in a position to offer you terms to suit - eg if your course is 3 years, they can give you a loan that you have to pay off within 5 years, and hold off starting the repayments until year 4 (ie when you finish uni and start working fulltime again).
Of course this means that you are facing into debt when you complete uni and start working again, and have to pay off what is essentially a 5 year loan in 2 years, but anyone I know who returned to education having to give up fulltime work financed their way through college by doing this - working parttime to cover daily living expenses (you will have to be living frugally of course!) then paying off the bankloan debt when back out in the fulltime working force again.
Call to see your bank manager and have a chat, and see what they can come up with.
Depending on your degree choice, banks may be happy to offer you a decent sum as they will realise you should be in a good position regarding future earnings and thus able to meet repayments on the loan. You may need a guarantor on the loan though if pursuing this route. It's a tough choice to make to take on extra debt, but if it's something you want to do and think will benefit you in the long run, it may be the route you have to take.
You say you were thinking of renting out your house - would that put you in a better position - eg if the rent received would cover your mortgage, and you could then rent somewhere smaller and cheaper yourself for the three years?
The only other options I can think of to help are if you have a car loan out - sell the car, get a cheap runaround to do you, and pay off the loan ASAP so you won't have to worry about monthly loan repayments while you're at college.