From standard H7 normal (not high beam) headlight bulbs (assuming you don't go down the route of HID or LED retrofit that is in itself a world of potential pain), the easiest retrofit that is an improvement is to stay with H7s, but to upgrade to one of the enhanced brightness bulbs from a quality manufacturer (Osram, Philips, GEC, Bosch, Ring). These have all declined hugely in price in the last 18 months (about 50% cheaper since I was first looking).
Osram H7 Nightbreaker "silver" and "unlimited" models offer ~ 100-120% improvement on standard osram (or equivalent 55W) bulbs in terms of light output for 13-22 quid on Ebay for a pair. There is also an Osram "Laser" H7 model which offers +150% light output improvement for a few quid more but I understand there is a reliably-significant reputation for reduced lifespan on these. I have a pair of Osram NB +100% silvers on one of our cars which were a vast improvement on the originals, mid-white light that matches the osram LED W5W running bulbs in terms of colour temperature very well (2 years old for both and no issues so far). I have a set of Bosch +120% H7s in my £1 project car that give or take alignment issues are as good on dark country roads as the above Osrams. Finally, for my dolphin grey, I tried (very) cheap £10 LED H7s - they looked great, but only illuminated about 20 feet of road ahead and were awful in drizzle/mist, so after a couple of months, I replaced them with the above Osram 55W +100% bulbs, and then tried Osram Rally 80W bulbs - very yellow in contrast to the more modern 'nightbreaker' 55Ws, but my impression is that they project a bit further, fill the lightspace better, and owing to not being ultra-white, they are superb in poor visibility conditions (ie, driving in heavy drizzle or slight fog at night). As I use this car for overnight journeys Scotland to Plymouth, had I used them further I might really have appreciated the night-vision quality on these - I had the impression that you simply wouldn't get eye-fatigued for long trips in the dark (and oncoming drivers would be less affected by them as well as they are simply not as harsh as some ultra-bright modern bulbs). But of course, these aren't legal on the road, so I would suggest sticking to quality brand 'enhanced' bulbs at around £13-£22 a pair - they will be hugely better than any standard bulbs on your car at the moment. Happy to discuss further - best of luck!