Obama, Romney campaigns buy more ad time in Wisconsin

(CNN) -- With the level of activity in Wisconsin picking up this week, both presidential campaigns have bought a second week of ad time there, a Republican source tracking media buys told CNN.

The Obama campaign has booked $353,000 for this week while Romney's has purchased $205,000.

Separately several super PACs, including Restore Our Future, which is backing Mitt Romney and Priorities USA Action, which is supporting President Obama, are now on the airwaves there.

Following the selection of Wisconsin native Paul Ryan as Romney's running mate, Republicans had hoped they could make the state a battleground. CNN currently rates it as a toss-up.

Several new polls show President Obama with varying leads in the state. CBS/New York Times/Quinnipiac University showed the president with a 6 point advantage 51% to 45% over Romney among likely voters while a Marquette University survey had the margin at 54% for Obama and 40% for Romney.

Obama is holding a rally there on Saturday. Both Ryan and Vice President Joe Biden campaigned there this week.

After Romney went up there for the first time in the general election campaign buying $360,000 worth of ad time, the Obama campaign also bought time there surpassing what the GOP nominee had purchased.