If you can get a balance transfer you'll end up paying a % of the amount transferred but could end up saving yourself quite alot of interest. If you can get one then go for it but continue to pay more than the minimum every month you can afford to do so. Set a budget and stick to it (keep a spending diary if you don't know where your money goes) - every bit you can pay off will save you interest and make it easier to become debt free.
In the meantime pay the extra (the amount above the minimum payment) off the card with the highest interest rate. That will give you the most benefit as it will quickly reduce the amount of interest they charge and mean that you are paying off more of the capital.
If MBNA are charging you interest (ie. you're not on a 0% deal) then you'd be better to pay for everything with cash and not use the card at all.