The Limited.
Seriously, go there, the outfits are sorted by color and the entire thing is right there - and they are cut well for an hourglass shape. They have various styles - A-line, wide leg pants, pencil skirts, shorter or longer jackets, many of them belted...or a dress with a matching jacket...
And usually there is a 'buy a bottom get the jacket for 50% off' or something like that. Plus the material is stretchy, not confining like traditional suit-wear.
http://www.thelimited.com/Top-Look/August12_outfit_09,default,pd.html?start=22&ppid=c22&cgid=top-looks
http://www.thelimited.com/Top-Look/August12_outfit_15,default,pd.html?start=24&cgid=top-looks
http://www.thelimited.com/Top-Look/August12_outfit_22,default,pd.html?start=25&cgid=top-looks
http://www.thelimited.com/Top-Look/August12_outfit_27,default,pd.html?start=27&cgid=top-looks (think with a jacket)
Also, don't rule out buying tops/bottoms separately in basic colors...I found a great black skirt online at Banana Republic (the 'modern' A-line) that looks great with a white jacket from H&M and a solid shell underneath. Conservative, but fits very well. That might be your best bet if you're on a short timeline - one mall trip and you're done.
Definitely pay attention to your accessories, too...that will make or break the outfit. No scuffed shoes, simple jewelry, new-looking purse, etc.