Sunbeds are pretty cheap to go on, they vary from place to place. In saying that though make sure you don't go to some dodgy place just because its cheap, I've heard a lot of horror stories about it. Use a recommended salon.
I would at least consider a fake tan if I was you, if your going to be somewhere hot for 5 weeks then you probably don't need to be damaging your skin any more by using sunbeds before.
Fake tans are pretty good these days and don't make you orange! Again, if you can't apply a fake tan try a spray tan. Last year I had a St Tropez spray tan which was a lovely colour, it lasted about a week and by the time it had come off I had tanned quite a bit anyway.
If you do still decide to use a sunbed, talk to a professional about the length of time you need. With fair skin you would probably only need a couple of minutes a few times a week.