U.S. Rep. Michele Bachmann raised $4.5 million between July 1 and September 30, her campaign reports.

That figure could be the single largest fundraising haul of any member of Congress this quarter, including Florida Rep. Allen West, who reportedly raised $4 million in three months.

Bachmann, who is facing a strong challenge from hotel CEO Jim Graves, ramped up fundraising in the third quarter, ending September with $3.5 million in cash on hand. That $4.5 million figure includes the $1.1 million she raised in July and already reported in her pre-primary filing, the campaign noted.

Always a strong fundraiser, Bachmann had raised almost $16 million by the end of July, and spent nearly as much. Her brief presidential campaign left her with a nationwide network of conservative donors. According to her campaign, the average donation size in the third quarter was $45.

"I am humbled by the enormous outpouring of grassroots support for my campaign focused on keeping America the most secure and prosperous nation in the world," Bachmann said in a statement. "I am fighting aggressively everyday to create jobs and do everything I can to make life more affordable for Minnesota families, and I am honored to represent their voice in Congress."

The deadline for third quarter campaign finance reports is Oct. 15. The Graves campaign said it will release its numbers on Monday. As of late July, Graves had raised more than half a million dollars.

"Rep. Bachmann's fundraising figures are the direct result of her misguided priorities," campaign manager Adam Graves said. "She's spent her time fundraising out of state, catering to special interests and promoting her celebrity—all at the expense of Minnesota families. But no amount of money will cover up her six years of putting her own interests above those of the people she is supposed to serve."

The Graves campaign's internal polls showed him within two points of the three-term congresswoman. Bachmann, who was redistricted out of the Sixth this year, is churning out fundraising appeals, warning supporters that she is facing her tougest race yet.

As of late July, the sixth district was the second-most expensive House race in the nation. Only House Speaker John Boehner had raised more money.