Jul.19 (GMM) Reserve driver Markus Winkelhock says he can not afford to drive for Spyker beyond this weekend's Nurburgring race.

The 27-year-old has now been confirmed as Christijan Albers' European grand prix substitute, but a paying driver - either Christian Klien or Narain Karthikeyan - will take over for the final seven events in 2007.

"I am still the test and spare driver," Winkelhock explained to the magazine Auto Motor und Sport.

"Albers' situation means that I can sit in the car at the Nurburgring without a financial offering, but what happens after that, I don't know.

"You would have to ask Colin Kolles, but basically I need to find some sponsors."

Winkelhock also admits that completing a one-off drive alongside highly rated rookie Adrian Sutil, following less than three hours' private testing this year, is a hard task.

"Adrian is really very, very fast -- substantially faster than most could have predicted. He was regularly half a second in front of Albers," he said.

"So I will simply get into the cockpit and give the maximum from myself and from the car."