How can I apply robust regression to multi linear regression?

Hi everyone, I am trying to apply "robustfit" for multi linear regression "regress" , I have y and x1 , x2, the problem that I faced with correlation coefficient, with regress I got one value for R2 while with applying robustfit I got a diagonal matrix (3x3) for R2, my question how can I get one value for R2 with using robustfit with multi linear regression,

Thanks in advance,

Riyadh