brought a mk1 fabia vrs from a garage dealer and it came with HIDs and one of the bulbs have gone I'm stuck with what sort of make the kit is to buy some more

bulbs?

You need to fine out if its a 35watt of 55watt kit, ebay has load of bulbs in different colours. 

As above member states, check bulb for identification wattage stamped on bulb base ?

ive managed to find out that the ballast is hella?

 

just finding out on a bulb

Your bulb will be H7 what wattage it is is the question. For the sake of it but 2 at 55W and fit them.

If they are genuine HID / xenon headlights, the dipped beam bulb will be D2S, 35 Watt

And also if th3 ballast is 35w and you buy 55w ypu will not have goof results, make sure you check.