curve fitted ... how to retreive data

Dear R users, 

I have now managed to fit the curve using the thin plate spline as follows:

library(mgcv)
b <- gam(y~s(x1,x2,k=100),data =dat)
vis.gam(b)

What I want now is to get the fitted data for y and copy it so that I use it for further analysis. 

Many thanks in advance

mintewab