Hi slaske,
it is untrue that a person that is a little overweight has a slower metabolism, in fact the heavier you are the more calories the body will burn in its basal state.
It is important to break you daily calorie intake into small regular meals. For example 5 or 6 little meals, 1 every 2 -3 hours. This way your body will have plenty of time to digest and assimilate the nutrients that you are giving it. And you will find that you are less hungry throughout the day.
Each meal should contain the components of carbs, protein and fat. The quantities of each would be determined by your metabolic body type.
Try to ensure that you get a good source of fibre with each meal e.G. Brown rice, wholemeal bread, wholemeal pasta, etc.
Plenty of water is also needed to ensure correct bodily processes to take place.
Regular exercise and increased active daily living will also make a large difference to how your body burns fat. So if you can catch the bus further away or walk faster than normal, these are all cheap and effective ways to push your body further.
I hope this has been of help.