If they are standard filament bulbs and are after a simple upgrade, look for some quality Hella/Narva or other branded + output bulbs. Normally in like +120% or +150% etc etc. Bear in mind, this comes at the expense of bulb life
If they're the factory HID units, boon's suggestion should have you covered.
Side note, @boon when you went to Philips bulbs, did you stay with the OE 4300k colour or venture out for something different?
Another thought, on the right hand side lower dash, to the right of the ignition barrel is a little switch panel. On that panel there could be a little scroll wheel numbered 0 through to 5. This is the headlight level adjuster, used to lower the headlight aim based on vehicle load, when you're towing, full boot, 5 passengers etc.
If your car is empty (light) the scroll wheel should be on 0, if you're car is fully loaded (heavy), scroll the number up as you need. This lowers your headlights as to not blind oncoming cars when you have a full load (which lowers the rear of your car causing headlights to aim abnormally higher thus blinding)