The Gunners currently sit in third place, four points ahead of Chelsea, five clear of Tottenham and Newcastle, and seven clear of Chelsea.
With five games remaining, a higher-than-fourth-place finish is looking more likely but the unpredictable nature of the top flight means nothing is set in stone yet.
Wenger told reporters: "We want to win the title. It depends how we finish to decide how many we need to buy.
"Our policy has not changed: to be ambitious and spend the money we have available in a wise way.
"We must maintain our momentum, and try to finish above last year's position."
Wenger is wary of Monday’s opponents, Wigan, which has beaten Liverpool, Stoke City and Manchester United in its last four matches, while giving Chelsea a run for its money.
“[Victor] Moses and [Franco] Di Santo are a threat,” the French coach observed of the Latics' front line.
“They are solid at the back, too. They are a well-balanced team.”