Average With Multiple Conditions, Including Dates

My spreadsheet is too large to attach so I'll describe it as best I can. I have names in column H, which are repeated irregularly. I have corresponding grade numbers (1-5) in column I, and I have the dates they were entered in column J. It looks something like this:

Column H Column I Column J
Name 1 4 8/10/08
Name 2 3.5 8/11/08
Name 1 5 8/11/08
Name 5 4 8/12/08
Etc....

I want to average the grades (column I) for a certain name (column H) within the last 30 days, or however many days I enter. I'm using Excel 2003 with the analysis add-in. I can use SUMIF to include any two columns, but how can I write an average grade formula using both the name and date conditions? Dan Auto Merged Post Until 24 Hrs Passes;Come to think of it, all I need to do is sum the data. I have a denominator in a different box that I can use to average it. So in effect, I'm trying to creat a SUMIFS function.