Changing the side lights to LEDs wont make a real difference at night. As srhutch says - raising the beam works. Alternatively, you can fit an HID kit or retro fit xenon units
I've had both pre and post facelift xenons. The pre facelifts were brighter as they had halogen and xenon high beams. The post facelift only have xenon high beam.
If you're going down the retro fit route, it'll cost you a fair bit. Typically xenon units go for £450 (ish) in the 2nd hand market.
If you install an HID kit, watch out for MOT failures - as you're supposed to also fit self leveling units and headlamp washers.
Good luck