not looking to flame rowan as you put up good reasons not to get a loan.. but the debt will reduce over time.. so interest will reduce over the period.. hence why mortgages start off high payment with very little principle being paid off..
i suggest you use rowans advice but look into the total cost, the bank should inform you of fees and total interest paid over the term of the loan (this is by making the repayments calculated by them.. also if you pay it off quicker then less interest will be charged.. you can then use the money saved off that interest to offset the loan (obviously the less money you give to the bank you can pay the loan off)..
now why do i feel like my parents after saying all that