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Hello I just got here last July and they last time i check the UK Boarder rules is that you need £18,000 a year ... anyway just check it yourself to be sure as they always change the rules here is the website:http://www.ukba.homeoffice.gov.uk/
My advice to you is that you contact the boarder to ask them how you can get your wife if just in case you can't reach the requirement maybe they will have some suggestions.
Hope I help even a bit. Good Luck to both of you.