I reckon the easiest way is to use VLOOKUP still, but have a user
defined function to extract the text from the textbox. Like this:

Function blah()
blah = ActiveSheet.OLEObjects("TextBox1").Object.Text
End Function

To establish the name of the textbox  ("TextBox1" in the function
above) you may have to right click the text box and choose Properties,
and replace 'TextBox1' with whatever yours is called.


Used it a spread sheet  in a cell  by itself it would look like this:
=blah()

Used in the VLOOKUP function it might look like this:
=VLOOKUP(blah(),B12:G18,3,FALSE)