In reply to AndrewJYoung:
Many factors to be taken into consideration and your profile doesn't give much information about you. How long have you been climbing? What grade to you climb now? What type of climbing are you most interested in, boulder, sport or trad? Goals?
So in very general terms:
There are good bouldering walls in Bristol I believe. These are probably the best way to improve strength and learn technique. I think going at least 3 times a week should be enough, though you need to get enough volume and intensity to keep improving. That means doing enough problems of sufficient difficulty each week. You also want to figure out your what type of climbing you're worst at and concentrate on that: might be slopers, fingerey stuff, roofs, slabs or whatever.
For books I agree with '9 out of 10 climbers' and also add the old but excellent 'Performance Rock Climbing'.
Cardio is not necessary for climbing. If you want to do that and fit it in though will depend on how much you're doing, how fit you are etc. Too much will detract from climbing training a bit - unless its helping you lose weight. If you're not doing too much it can even be used a good warm up before climbing - eg. 30 mins jog or bike ride to the wall.
There are also loads of online resources worth checking. TrainingBeta.com has good podcasts you can listen to while doing other things. Others include
trainingforclimbing.com
allirainey.com
Plus you can also mine the forums on here for info.