Though not the exact same model, your watch looks quite similar to my Y759-5019. I looked on Digital Watch Library and coudln't find your exact model. I also did a quick Google search and didn't come up with much.
I recently tried replacing my battery. My Y759-5019 takes a CR2012 but I couldn't find them in any local stores (drugstores, Walmart, Target, etc.) I thought that they were no longer made but after a search online I found plenty of sources. I ended up ordering from Amazon.
If you need instructions you might try searching Digital Watch Library for the manual for Y759-5019. Since yours looks similar, I'm guessing that they use the same module. The instructions are probably the same. Good luck!
Here is a pic of my watch. :)