Your mare isn't really tall, so trying to get a 16hh or 17hh baby probably isn't going to happen, not to mention that she's not really 'typey' for english. I would love to say that doesn't matter, but I show a 15hh paint English, and I'll tell you--its frustrating when taller horses win in under saddle classes... just because they're taller. Argh! It doesn't happen all the time, and if you want to just stay local then I'd say go for it. But I know height is super important in quarter horse, so in my opinion... I'd say go for a WP stud.
With that behind said, look for one with a somewhat short back, a little more height, and a niiice neck--your mare could use a little in the nice-neck department. But I love her face and she has that nice low headset--depending on her movement, I think you'd get a lovely WP baby from her.