If you want this for a specific function you can just create the function directly:
>> g = @(x,y) [2*x,2*y];
>> g(1,1)
ans =
2 2
Using the symbolic toolbox you can do the following:
syms x y
f = x^2 + y^2;
g = gradient(f,[x y]);
subs(g,[x y],[1,1])
or if you really wanted this in a single function:
syms x y
f = x^2 + y^2;
g = @(x0,y0) subs(gradient(f,[x y]),[x y],[x0 y0]);
