The multi-brand dealer is Germany's fourth-largest dealer group after Emil Frey, AVAG and Mahag.
Company boss Burkhard Weller said that growth is only possible now through conquest.
Weller will open new locations in Berlin, Bremen, Buende, Bad Oeynhausen, Leipzig and Detmold by 2007.
The group plans to sell 40,000 cars and achieve sales of 650 million euros this year.
Last year Weller's 23 showrooms sold more than 32,000 vehicles -- 9,355 new and 22,660 used cars.