You should be able to get it going. I have been able to revive some liquid yeast on more than one occasion, both ale and lager.
The thing I have noticed with the initial starter when the viability is low and the yeast is old is that the initial starter shows very little if any activity when compared to a fresh vial. I generally place a small (usually 1L), low gravity (1.020-1.030) starter on the stir plate for about 48hrs. Then chill and decant. Then, depending on the size of my target beer I make a slightly higher gravity (1.040ish) 4-6L starter. I usually see the typical starter activity in my step up stage before pitching.
My guess is that the yeast is fine, but that you will see little if any activity. I would do a minimum of another starter step up 2-4x's the size of your current starter before you pitch (if that is possible?). In addition, maybe even place some fresh wort from your brew on brew day onto your chilled and decanted second starter so you are pitching active yeast?
Hope this helps, and good luck!