i was audited for my 2013 return i claimed my gfs kids and wasnt supposed to i have to pay back all the money i got returned can my gf now wife claim the kids for that year

it depends; she can claim the child aslongas she meets the requirements to claim her kids as her dependents;
the kids must have t lived with her for more than half the year; the kids did not provide more than half of their own support during the year.