The Gunners currently sit in third place, five points 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.
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"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, who have beaten Liverpool, Stoke City and Manchester United in their last four matches, while giving Chelsea a run for their 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.”