Calculating of vectorial field using numerical integration

Hi

i need to calculate a distribution of electric-field E[],

I've got the analytic formula which is

E(X,Y,Z) = integration over x1, y1 of the function -

           e(x1,y1)* F(X,Y,Z; x1,y1; i) dx1 dy1

when e(x1,y1) is a function i created using symbolic math and made it a matlab function, can be seen in the link below - http://mathworks.com/matlabcentral/answers/32415-calculating-of-multivariate-symbolic-expression-with-numeric-data#answer_40977

and F() is an exponential complex function.

do anyone know what is the best/efficient way to calculate it? and how?

10x