I second what jaz says.

Thing to do is hit the worst offenders first.

Sugar loaded drinks are absolutely the worst thing for weight control (and that includes "Natural" fruit drinks and sugar in tea/coffee etc) and your health generally - they massively raise your insulin making you hungry all the time, not to mention rotting your teeth and putting you at risk of diabetes.

Next on the list is anything else with high refined sugar content.

Next thing to eliminate is starchy white foods.

Tackle those and you will feel less hungry due to reduced insulin levels so a virtuous cycle kicks in. Then you can work your way to a more hard core program as jaz outlines.

As far as exercise goes, despite popular belief, weight/resistance training is actually much better for weight control than lots of cardio/running and has lots of other benefits such as increasing your bone density, lean muscle mass, ligament and join strength etc. Buy a cheap ass barbell and weights (from tescos or something) and do some dead-lifts at the very least.