Calc Implicit Differentiation Problem?

Okay, so I'm trying to do my Calc homework and for some reason, I'm getting stuck on a differentiation problem.

So, it's basically (sin(x)/(x))+(sin(y)/(y))=C, where C is some constant. Obviously the constant would disappear, so I get: (after simplifying)

((xcos(x)-sin(x))/(x^2))+((y'cos(y')-sin(y'))/(y'^2))=0

My problem is getting a y' on one side of the equation and the rest on the other side so that I can solve it. (Provided I actually differentiated it correctly above...)

I do have one point on the curve, (pi/3, pi/4) if that helps at all, but I need to get it to the point where I can plug in a value for x and get the y value, and I'm kinda stuck.

I would really appreciate any help. :-)

Thank you!