Excel 2007 :: Lookup One Value And Returning Multiple Values (Horizontally) With Two Sheets

I'm basically working from 3 sheets for this so I'll start with an example of the data I'm using:

1st sheet:

table.tableizer-table {
border: 1px solid #CCC; font-family: Arial, Helvetica, sans-serif
font-size: 12px;
}
.tableizer-table td {
padding: 4px;
margin: 3px;

[Code]....

I have 180 rows of data like this one in the first sheet

Second sheet(named sheet 1) is not used for this

Third sheet(named sheet 2):

table.tableizer-table {
border: 1px solid #CCC; font-family: Arial, Helvetica, sans-serif
font-size: 12px;
}
.tableizer-table td {
padding: 4px;
margin: 3px;

[Code]....

Basically I'm trying to find column #3 value in my third sheet and return the second column value. Problem is that the data is located more than once in the third sheet so I need the value of each one of them. So, with this example, Q5942X is located twice in the third sheet and each time, it has a quantity of 2. I would need either to return the value 2 twice horizontally or even better, add the two together. The first sheet, the example is row #45.

This formula should be in the column following "majoration".

I am using excel 2007 and windows 7.