Id like to get fitter, what distance should i go for in swimming+in the gym... pls read on...?

You need to strive to do a little better each time, push yourself a little bit more. If you do 5 laps of the pool aim for six. If you lift 50kgs then try 55kgs. Each time you will be building yourself up, getting stronger and fitter. Eat healthy, and keep exercising.