In the Fit Model dialog, you can uncheck the "Center Polynomials" option. I think that's what you meant by "unstandardized" coefficients.
Delta for calculating power is whatever you decide it is (though I don't know what you mean with the R^2 in parentheses). It is the effect size you want to be able to detect. You can use the Evaluate Design platform to get a power analysis. Delta would be the coefficient size you input in that platform.