Existing code to calculate confidence intervals after GMM using the Delta Method?

Hello all,

I am a graduate student in the University of Maryland's Agricultural Resource and Economics Department. I just used the GMM Library written by Mike Cliff to estimate a non-linear model, and would like to use the delta method to calculate confidence intervals around some model predictions.

I was hoping that there was an existing toolkit or function I could use to generate the confidence intervals. Is there existing software I should know about?

Thanks very much for your advice (it is genuinely appreciated),

Seth