I agree with bednobs lowering the payments isn't an option.
You don't appear to have taken into account the interest on the 7 year loan, so you will be paying a great deal more then 5000 pounds back.
With regard to the credit cards, in order to continue taking advantage of 0% deals you'll have to apply for more credit cards in either November or December 2008.
I would get rid of the payment protection & put that money towards the loan.
Go to the library & borrow a copy of Martin Lewis' Money Diet book or visit the website
http://www.moneysavingexpert.com/. You need to look at minimising your current expenses - see if you can make savings on rent or utilities, even ordinary things like bringing your own lunch to work every day can make a difference.