“My job is to mobilise the resources to achieve that. I have been given two more years.
“So, we will work and fight to make sure we prove ourselves in the 2008 season,” Yamashina added.
Jarno Trulli and Ralf Schumacher amassed just 13 points in 2007, with a highest finish in a grand prix of just sixth.
Toyota will launch the TF107’s successor, to be raced by Trulli and newly crowned GP2 champion Timo Glock next year, on January 10.
Yamashina said: “This year’s experience brought home to me the fact that we have lot of work to do.
“We need to continue to push hard to arrive at the top.
“Our goal at the beginning of the year was to lead the second group and gradually reduce the gap between us and the two top teams, but in the end it was proved that we had been too optimistic,” he admitted.
“We studied our performances in 2007 and we believe we have found areas where we have to improve. We expect more from the aerodynamic side and also from an operational side but I am optimistic that the team knows what needs to be done to improve our performance.” (GMM)