Thats already a decent amount to spend on lights. What kind of yield you'd want/expect? What is the size of your grow space? What strain are you growing, whats the size of your pots?
If you want to buy european to avoid taxes and long shippings, there's a couple of good companies to deal with.
I use myself the Hans panels, for 400 quid you can get 3 of them and can cover almost a 4x4. (2x4 + 2x2 or concentrate them in a 2x4). They are small, use few electricity and are quite easy to deal with. The bad side is that they arent that powerful so its best to use them for small rooms or scrog setups. My plants are never taller than 2.5ft.
http://www.ledgrow.eu/
Then theres Plant Photonics wich has a good reputation. I never used them myself and there's few reviews on the net but you still can find some. Some members on here have them, make a research. They seem well build with good parts.
http://www.plantphotonics.com/catalog/index.php
Then there's offcourse Viparled but the parts arent that good as the others. They seem to grow good weed tho, plenty of threads on here and other forums with growers using them.
If you're willing to buy outside of Europe, then for your budget your best bet is Area51 XGS190 or RW150. They both cover a 3x2.5 in flower. Good reputation, good parts, good service. I own one, the XGS, and Im very happy with it.
http://a51led.com/store/
You also have Rapidled's Onyx wich can also do the job.
http://www.rapidled.com/bloom-onyx-by-rapid-led/
These are specific: one for veg, one for bloom.
Its up to you and how you'll use it. Good luck!
*ooops I see you already made a choice
2 x B3's should do it well enough, but then they have their new C series, but thats not on their site, only ebay...