Central Locking

[Raza]

Hi everyone,

I've recently bought ford fiesta (finesse) as my first car in UK. IT's a 2003 Petrol (1.3) . I needed to know about it's door locking system as it didn't come with the remote. and everytime i need to lock it with the key, but by locking just one door (driver) all doors get locked . how can i convert it to remote locking system by cheapest way ?? as it's an old car so don't want to spend much on it.

Any suggestion and guidance will be much appreciated. 

Thanks in advance.

Best Regards

Raza