Hi Polly wolly,
I'd agree with what the others are suggesting (i.e. clear your debts first).
I'd recommend doing the following:
1. Assess your spending (work out where you're money is going and try and eliminate unnecessary spending i.e. cut out starbucks if you have free coffee at work etc - it seems trivial but you'd be amazed where you're money goes and how much spending you can cut out). You could keep a spending diary of all purchases you make over a week or two to help with this excercise.
2. Analyse your debts ordered by most expensive first and start killing off the most expensive debts you have first (The interest rate is the "price of money", so if you're credit card is charging 15%, your car loan is 9% and your mortgage is 5% then you tackle the credit card first until it's paid by paying what you can afford each month as well as fulfilling your other debt obligations, then the car loan - details on mortgage below).
I would really recommend against remortgaging over a long term in order to pay off short term debt (if you work out how much you actually end up paying back you'll see why) - some mortgage providers (such as first active) offer split term loans (i.e. you can have a 5 year loan for your short term debts such as car loan etc and then a 30 year loan for your house). This may be a better option but it really will depend on your circumstances.
3. Once you have cleared all bad debt (unsecured debt - credit cards, car loans, personal loans) you now may be in a position to invest.
The reason you need to tackle the unsecured debt first is because you'll struggle to get the same rate of return on an investment as you would be paying on your credit card for example.
What to invest in then depends on your risk profile, your timeframe, your preferences (how much time you will spend researching, what type of asset classes interest you the most (property, shares etc).....etc).