+1 to sam, you're asking for something that doesn't exist.
What does exist, however, is the Sapphire Radeon HD 7870 XT with Boost (http://www.amazon.co.uk/dp/B00AX2ONI0/?tag=pcp0f-21), which is only marginally weaker than the 7950 and falls only slightly above your target price. Should be able to handle the majority of current games on high settings.