You want a 2005-2008 Sline bumper and need a 2005-2008 Bonnet along eith foglights and fog grilles
AUDI A3 Mods; Genuine S3 18" wheels, Single Grille conversion
You can use sport or s line bumpers up to 2008 where the shape changed to 8p3. You'll also need a new bonnet up to the same year. A quick search will throw up a selection of guides and similar threads for you. Here's one for starters My SPORT to S-LINE Conversion (Part No's, Prices & Tips included)...
A3 3.2 Quattro Sport