Hello and welcome to the site. Thank you for your question.
All taxpayers are entitled to a personal allowance in their own right. You are right in assuming that your wife will have her personal allowance to cover her small pension of approx £4,500 pa.
You would claim your own personal allowance against your income. You would be entitled to married couple's allowance.
Taxpayers who are part of a couple, one of whom was born before 6 April 1935 are entitled to the married couple’s allowance. The married couples allowance is £8,355 in 2015-16 (2014-15, £8,165), but relief is only available at a rate of 10%. Therefore, the maximum reduction to your tax as a result of receiving the allowance is £835.50 (£816.50 in 2015-16).
More information on married couple's allowance can be found here
Furthermore, in 2015-16, married couples and civil partners will be able to share some of their personal allowance between them for the first time. Unused allowance from one partner can be used by a higher-earning second partner to save tax. The amount you can transfer is capped at £1,060 in 2015-16. Mr Osborne noted that this will increase to £1,100 by 2017-18. Only couples who are both 20% taxpayers can transfer allowance in this way.
I hope this is helpful and answers your question.
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