Yes. What data. Where is it? Named ranges? Does this third file  exist or do you need it created automatically? Are you overwriting data  or adding it each time?

Try to spell out exactly what you need, e.g.

Copy data from Sheet1 of WB1.xls range A1:L1 - paste as the last entry of WB3.xls Sheet1 rows A-L. Copy data from Sheet 2 of WB2.xls range A1:L1 and paste again as the last entry of WB3.xls Sheet1 rows A-L.