In the past seven days, Winning Our Future has spent $61,290 on broadcast television advertisements, compared to $636,920 spent by Mitt Romney and a super-PAC backing him, Restore Our Future, according to data compiled by New York-based Kantar Media’s CMAG, a company that tracks advertising.

For now, the Adelsons don’t plan to deliver another big check to float Gingrich’s campaign, according to a person familiar with their deliberations. The family has donated a combined $11 million to Gingrich’s super-PAC in the past two months, according to interviews and Federal Election Commission records. An Adelson spokesman declined to comment.

Gingrich’s shifting fortunes offer insight into how the rise of super-PACs and wealthy donors in the 2012 presidential can change the dynamics of the contest in a short period of time.