I'd say if you don't want to spent a lot of money you can connect an "amplifier" (I don't know the proper word in english sorry) for the lights, consistinf of 2 relayes and a fuse connected in the lights's wires and with a pair of H4 100W bulbs you can do the job. Total cost in Greece where I am from incl. bulbs about 40 pounds!
I've done this in mine and the difference is huge!!! I'll post a couple of pics when i'll find some time.