How often???? How, often

I've recently started a diet and i've also been doing some gym work in this... I've been doing some weights 3 times a week but how often should I be doing any cardio workout?? The reason I ask is because i've been doing it every day almost (i've had 1 day off so far) and it seems a bit much going down the gym every day, i've also read on some websites that I should be doing it 3/4 times a week so what do you lot recommend should I go for 3/4 times or 6/7 times a week??? i've been doing 45 minutes cardio each time by the way

What are you goal's from cardio?

My goals are obviously to lose weight, I drive a bus for a living so spend between 8-12 hrs a day sitting on my arse so doing a bit of excersise is important

Just my opinion but try to do your cardio either in the morning Or after your workout.  If you are just trying to lose weight, try to control the eating habit.  Nutrition is key to losing weight, heck if you can burn 500 calorie more a day than you intake; you will lose 1 lbs a week.  This generally does not work because 1) people under-estimate how many calorie they consume in a day, and 2) they over estimate how much calorie they burn.   
In general, the most ideal weight lost should be about 2 lbs a week.  Basically, a defecit of 1000 calorie a day (500 from dieting and 500 from excercise)  Its really tough to do but doable.  Just know that the first few weeks of weight lost is water weight but use it as a boost to keep you motivated to go to the gym.  Initially, find things to keep you going back to the gym and staying a little bit longer on the machine to workout.  Normally, I try to stick to minimal of 30 minutes of cardio each session and try to go at least 3 times a week; with the goal and time permitting, 60 minutes and 6x max a week.
It's just my opinion and congrats on taking the first step to a healthier lifestyle.  Oh btw, think of it not as just trying to lose weight but a lifestyle change.

Thanks mate... To me it aint just weight loss as its about time I got myself fitter as I was starting to let myself go