ListBox ( finding supporting data not in the list)

[TK]

Hi:

In the following: column A and B are used as listBox items in a pickList
C, D and E are suporting data but not in the listbox( they
could be).
1 A B C D E
2 PickList Area per Sq' Cost Accessories Total Cost
3 Plywood 32 1.00 0.25 1.25
4 Patio Block 1 2.00 0.15 2.15
5 Paving brick 4.5 3.00 0.35 3.35

In another part of the workbook items can then be picked from the
piclklist.
A formula in column E then calculates the amount of items needed.

11 A B C D E
12 Item Area per Sq' length width Total
13 Plywood 32 8 8 2
14 Patio Block 1 3 3 9
15 Plywood 32 4 8 1
16 Patio Block 1 1 2 2
17 Patio Block 1 22 2 44
18 Plywood 32 12 8 3
19
20 Then a =SUMIF will total and display the summed items.
21 A B C D
22 Item Amount Needed Cost Total
23 Plywood 6 ? =C23*D23
24 Patio Block 55 ? =C24*D24

The question is how do I refer back to the items' cost from C23.
In that case Plywood (cost = cell E3).
and then from C24 in that case Patio Block(cost = E4)

I have tried some if statements with loops but mine seem pretty clumsy.
Any guidance or example will be greatly appreciated.

Thanks
TK