The team's young Finnish 'Friday' driver is hotly tipped to be Pastor Maldonado's teammate next season, having impressed the British team this season.
In his 14 morning practice outings in Bruno Senna's car this year, he has outpaced Maldonado a credible 6 times.
Still, Williams is yet to announce its decision.
"We need a little more time," 23-year-old Bottas is quoted by Turun Sanomat newspaper.
"It could happen in 5 minutes, or on the 31st of December," he explained. "But they know that there is a lot more to come from me, as long as I am able to do more driving."
As ever in modern F1, however, money is a factor. So does Bottas need to find some more powerful backers?
"I hope that's not the case," he answered. "But these days the role of money is big, especially in the beginning for a new driver.
"I have some Finnish sponsors, but not as big as some of the others have to offer."
In the meantime, Senna is hoping to hold on to his seat for 2013, even though the well-backed Brazilian has reportedly also been in talks with Caterham.
"Every year I go to a new team," the frustrated former HRT and Lotus driver is quoted by Brazil's Globo.
"So it would be good to have some sort of stability. For sure, this part of the year is not the most comfortable when you don't have a contract," Senna admitted.