Table Copy/Append/Update Question

I have a series of .csv files created by a parts system. The .csv filename is in the format partnumber.csv The csv file contains a date column and 6 other fields. Each csv file is about 4000 records and there are approx 7000 .csv files that get re-generated once a week.

I'm using c# SqlBulkCopy object to import the csv file into a temp table. No problem there. It works realy fast.

What I need now is a way to move the data from the temp table to the final table and append the partnumber. I'm thinking it would be easy to pass the partnumber in as a paramerter to a t-sql query but not sure how to write the query itself.
I also want to check if the partnuber/datestamp combination from the temp table already exists in the final table and skip it if it does. So I suppose I ultimately need an update query.

Once I have that query written it's easy to import a .csv, launch the update query, wipe the temp table and repeat with the next .csv file.

Temp Table Layout: DateStamp(datetime), Field1 ... Field6(all real's)
Final Table Layout: PartNumber(varchar), DateStamp(datetime), Field1 ... Field6(all real's)


TIA.