This is custom macro territory. You can find text and highlight every instance in 2003, using the Find feature, but capturing and copying the entire line in which the text occurs would require an addition to the macro running this function. It might be a simple as adding one or two lines of code, but it's out of my league.

Allen Wyatt's WordTips.net sells an inexpensive e-book on Word macros, including hundreds of macros and some basics on creating these special routines. You may also find assistance from developers' sites, if you poke around the web a bit for Word macros, Word assistance, free macro help, etc.