It doesn't have to be Behringer.
Here's one that is 2x300 watts into 4 ohms.
http://www.peavey.com/products/shop_online/browse.cfm/action/details/item/00511500/wc/2A2C1/fam/2C/tcode/1/v.cfm
Alternatively, there should be a whole heap of poweramps floating around on eBay. For nice and cheap.