Ok my car at the moment is a bit of a shed

the bonnet has almost all of the laquer missing and looks like a red chalk board

Could i use spray cans to make it look better? or is a bonnet to big for the cans pressure? never painted anything before, assume i would still have to sand it smooth and then primer it first?
How would i go about laquering it after? any tips would be great
If you cant find a bonnet your colour, well...
You could also just try removing the rest of the laquer, then renovating the paintwork. and before everyone says "rubbish!" (or things like that) just hear me out...
Most paint finishes since the late 70's have been 3 stage - primer/undercoat, the colour which dries flat and dull, then a clear laquer which gives depth and shine. But the basic paint itself will take a good shine without laquer if you know how, although it takes some effort. I know, my first job leaving school was in a body shop. Here's how...
Some time ago I bought a green Rover in which several panels had really bad laquer peel, the car looked like a shed, yet there was little rust. So I took some 1200 grade wet/dry sandpaper and ground off the rest of the laquer on each panel. You need a bucket of warm water and a bar of soap - wet the paper, rub it on the soap then carefuly sand the laquer off, being careful not to rub through to the metal! Keep the area wet with plenty of soap, and wipe the area dry regularly to check you have removed the laquer and exposed the paint.
When its all done go over the panel with some Brasso (yes, really, Brasso!), perhaps more than once, some T-cut, then follow with several coats of polish. You will be amazed at the finsh you can achieve with patience - the person I bought the car from certainly was, he thought I had re-sprayed it! Obviously without the laquer coating you will need to keep it polished from time to time.
This all might sound a bit brutal but if the paintwork is that bad anyway what have you got to loose? Its very cheap, all it cost you is some time. I had the car finished in a day.