customer 'shows interest' in a product

I am designing all the standard relationships according to what I have learned. I now need to add another piece and I am not sure how. There are two parts:

1) when we are talking to a customer and if the customer displays 'interest' in one of our products, we want to quickly capture that and I think it should be a related table to Customers or Products. It would just log the timestamp, CustomerID, ProductID. Where would I relate such a table and how could I view a list of over 15,000 products quickly? actually, I think portal with global trigger to filter so I can probably figure this display part out. It is the relationship I question.

2) I have existing excel spreadsheet where I have the CustomerID and then a single note field. It holds things such as

3/17 I called about B8006 and quoted $127.50. 3/22 signed contract on G1182. 6-21-11 told customer that L3022 could be repaired for 27.50.

The bold are StockNumbers. Stock# is a field in my current Products table (along with a ProductID) and I keep it because it is a national cross-reference. I would like to find these stock numbers and then, once I decide how to answer 1) above, 'add records to this new table' for those ProductIDs.

I hope this made sense. Ideas of the best relationship and/or ideas on getting these old stock numbers into new records would be really appreciated. I just sit here and scratch my chin.