whatever you do don't spend a lot, keep it to a min as you wont get much more power out of it being a 1.3.

i also wouldnt bother going carbs as it'll be shit on fuel and not as nice to drive as fuel injected and they'll require a fair bit of setting up.

personally, i'd do a service and make sure its running 100% and then save the rest for something better in the future.