Allen and Radtke show off their campaign cash

Washington (CNN) - In what could become one of this cycle's most expensive Senate battles, it appears Republican George Allen is planting the first flag.

Allen's campaign reports that the former Virginia governor and two-term senator raised $1.5 million in the first quarter of this year.

Allen announced his bid on January 24 for what is now an open Senate seat, which means he brought in an average of $150,000 per week since he announced his bid. A source confirms to CNN that Allen's fundraising included donations from each and every county in Virginia. The figures were first reported by Politico.

"Our race will be hard fought and very likely determine control of the U.S. Senate and the direction of our country. I look forward to continuing to build a strong team of grassroots supporters who will work to bring the voices and values of Virginians to Washington," says Allen in a statement.

Allen lost his 2006 re-election bid to Democrat Jim Webb, who announced earlier this year that he wouldn't run for re-election in 2012. Allen's numbers give him a head start on the Democratic candidate, Tim Kaine. The former Virginia governor announced last week that he was stepping down as chairman of the Democratic National Committee to run for the open Senate seat.

Allen will have company next year in the fight for the GOP Senate nomination. Jamie Radtke, the head of the Virginia Tea Party Patriots Federation, has already announced her candidacy before Allen jumped into the race. Her campaign says they've brought in over $150,000 since Radtke declared her candidacy in late December.

"We had two goals this quarter: put together a solid campaign organization and raise $50,000. Our treasurer is finalizing a few numbers, but we exceeded both Q1 goals and we've already raised over $150,000 for this campaign, which puts us a year ahead of Jim Webb in his race against George Allen in 2006," says a statement from her campaign. "We always knew this would be a grassroots versus establishment race; the establishment money comes early, the grassroots and Tea Party money will be there when it matters."

–Follow Paul Steinhauser on Twitter: @psteinhausercnn