Excel graph extrapolation

I’m trying to figure this one out at the minute. I'm trying to recreate a graph and Regression value in excel to represent data generated by one of the software programs in a biochemistry lab. I’ve included an excel worksheet with the data I'm trying to recreate and the original standard curve from the lab program. Would you have any idea’s as to how I can do this in excel? The graph is a 4 point polynomial graph but I can't get the data to represent that generate by the program as I can't extrapolate past the max and min values of my graph for the protein heavy chain and light chain. Could anyone help me to recreat this data in excel? And just to let people know that I would be considered a novice in excel at best so please remember, small words for me (baby steps if you will).....

Thanks in advance