Audi is moving from strength to strength the world over but especially here in the U.S. where for years brand prejudices has left it playing second fiddle to the likes of BMW, Mercedes-Benz and Lexus. The four-ring brand is in the midst of a transformation, however, and is set to launch a host of exciting models over the next 12 to 18 months so grab a seat and let’s look at the rundown.

This past month Audi’s U.S. sales rose 26% to achieve the brand’s second-best August sales ever and its best month overall since June 2008. In August 2009, Audi sold 8,057 cars and SUVs compared to 6,406 vehicles sold in August 2008.

By the end of the year we should be seeing Audi’s awesome R8 V-10 supercar hitting the streets, as well as the S5 Convertible and S4 Sedan. However, the real action starts next year as Audi is planning to unveil a replacement for its A8 flagship sedan, the production version of its A7 four-door coupe and possibly the next-generation A6.

First comes the 2011 Audi A8. Speculation had put the world debut for the new aluminum space-frame sedan sometime this fall, but it's now certain that the A8 will make its world debut at the 2010 Detroit auto show. The car will be “the first of a new styling language at Audi,” executives say. All-wheel drive will be teamed with dual-clutch transmissions and a range of diesel, turbocharged V-6, V-8 and possibly hybrid V-8 engines.

Next in Audi's busy year will be the production version of the A7 concept, shown earlier this year in Detroit and expected at the 2010 Geneva auto show. The new vehicle is a four-door coupe based on the A8 architecture, and will share its aluminum space frame. The same powertrains from the A8 should cross over into the A7, while an S7 version may sport a V-10 sourced from Lamborghini.

Last up could be a new A6, making its bow late in 2010 as the third model to arrive from Audi in the year. Few details on the new car have emerged, but German media have reported the new car is related structurally to the larger A8 and A7. The A6 will be built in a different assembly plant, so it's likely that it will remain a steel-bodied car--though like other Audis it will still feature extensive use of aluminum. A full range of four-, six- and eight-cylinder engines will appear with the new A6, as well as diesels. Quattro all-wheel drive and dual-clutch gearboxes will be offered. It's possible the new car could make its first appearance at the 2010 Paris auto show, but there’s no word yet on any release date.