This site goes over blood values in blood tests and what they mean - scroll down to the cells you want to know about
http://www.peteducation.com/article.cfm?cls=0&cat=1474&articleid=987
While the white blood cell count can go up due to issues including kidney problems, long term infections, and leukemia this age dog its apt to be a form of leukemia. You could try seeing if a round of antibiotics will help lower the WBC .
I don't think anyone can predict how long a dog will live unless there are only moments left.
I do think that as long as the dog seems OK you should do as many fun things you like to do together as possible.
You could choose to discuss the situation with a veterinary oncologist. This site may help you find one if you search on oncology and your state
http://www.acvim.org/Specialist/Search.aspx
Hope this helps you!
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