Do a search for tyre dealers in your area, personally I prefer local dealers than the national chains go to any of them and tell them your problem, then stand back. usually five minutes maximun for the job to be done. If you go to someone like Quikrip you'll likely to come out with 5 new tyres and a new silencer box for good luck, a local tyre shop may just repair the puncture.

Depends on the condition of the tire, and where leak is. Here in the 'States, very few gas stations still repair tires. If tread is good, and hole is not in or near sidewall, can easily be repaired by any tire shop. They can also replace tire as necessary. Check spare, it may be a temporary space-saver type, and for last resort.

Visit a tyre fitting garage and ask them to repair the leaking tyre.

All you need is to have the leak repaired at a tire shop.

the spare is for temp use. it is meant for you to get the car to a tire place, not to drive around on like some idiots do. chance are there is a nail stuck in it some where. take to the tire places and have them take a look at it.

sounds like all it needs is a puncture repair or resealing, much cheaper than a new tyre.

I'm a new driver so not sure about these things but I've had the car for a few months now and the front left tyre kepts going flat. I have several service stations near me but what do I do now? do I obtain the tyre myself or can they do this? I think I have a spare in the back.