If I park up hill the fuel drains away and so im unable to start the car and so i need to park facing down hill how can i start the car after this has happend?
I assume this is a diesel.
You probably have a leaky fuel return hose (also known as leak off pipes). This lets air in to the system and the fuel drains back under gravity.
The good news is it's a cheap and easy repair, very DIY-able if you are a bit handy.
I cant give specific instructions as you have not given the engine code etc.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cars.