American Crossroads, a Republican 527 group, is extending its television ad buy targeting Senate Majority Leader Harry Reid into a fourth week, according to an official from the group.

The extension brings the group’s spending against the Nevada Democrat to nearly half a million dollars.

The American Crossroads ad, “Really,” starts with shots of Reid’s own ad along with the Democrat’s tagline, “No one can do more than he can,” before showing a clip of Reid on the Senate floor saying, “Today is a big day in America. Only 36,000 people lost their jobs today — which is really good.”

Reid faces a tough fight this fall against state Assemblywoman Sharron Angle, the Republican nominee. Outside groups aligned with each party are expected to pour millions, mostly in the form of TV advertising, into the battle.

American Crossroads plans to raise and spend $50 million this year and advertise in at least 10 Senate races. The group is just one of several GOP organizations looking to get involved in the midterm elections this year. Look for a story on the web of Republican groups in next week’s Roll Call.