aless, if you can afford it, get one session with a trainer. talk about your goals and then have them set up a programme for you
that's what i've done. I've had a few, where they have measured my body fat % (scary) and we set goals and she gave me a number of weights to do for the weeks i don't do body pump.
then i meet with her in a few weeks for a short session so she can check i'm working out the right way still, then a few weeks after that i have a 6 week check up to check my % again.
it's actually a programme i spent £25.00 on only and i work with her 4 times, from measuring and goal setting to working out and monitoring.
I love fitness first for that, it was a great joining tool!!!!