
If you don't know when she came in season (though surely whoever was looking after her must have seen) then I think you would be better off waiting until the next season.
After all you will be tying up the stud dog owner for much longer if you are trying now, will cost you loads more in fuel if you can't stay away with her or board her with the stud.
In the normal event you'd be looking at up to a week for the mating period, like this it could be two..