For Gail Robinson, a real estate agent in Connecticut who has seen her business limp along since the stock market plummeted last year, it was the best news in ages.

With Congress considering a new tax credit intended to turn around the battered housing market, she hopes lawmakers have found the long-awaited silver bullet. She was busy Thursday sending out about 200 e-mails to potential clients about federal plans to give buyers a subsidy of up to $15,000 for all home purchases.

“My whole firm is excited about it,” Robinson said. “It could bring in a whole new set of buyers.”

The new credit, approved by the Senate Wednesday night, works like this: Buyers would get 10 percent of the purchase price of any home, up to $15,000, applied to their tax bill.

Consumers would be allowed to spread out the credit over two years, making it possible for those who pay less than $15,000 in taxes to benefit. Anyone who buys a home within a year of the bill’s signature would qualify. To deter speculators, buyers must occupy the house as their main residence for at least two years.

But the tax incentive is likely to be more helpful to buyers in less expensive markets, said Christopher Thornberg, a principal with Beacon Economics in Los Angeles. “Unfortunately, in the places that are most hard-hit, like California, it’s going to have less of an impact,” he said.

Sen. Johnny Isakson, a Georgia Republican and former real estate agent, introduced the new tax credit that’s estimated to cost the government nearly $19 billion as part of President Barack Obama’s economic stimulus package. It’s modeled after a similar measure in the mid-1970s.

A tax break passed last summer provides a $7,500 credit to first-time homebuyers. But that must be repaid over 15 years, and the impact on home sales has been negligible.

Homebuilders and Realtors argue that dramatic steps are needed to boost the shellshocked housing market. While sales of existing homes rose unexpectedly in December, prices are still falling rapidly. The nationwide median sales price plunged to $175,400 in December, down 15.3 percent from $207,000 a year ago, and the lowest since May 2003. Sales of new homes, meanwhile, fell in December to the slowest pace on records dating to 1963.

Lawmakers, at least in the Senate, appear to be falling in line, even as moderates from both political parties worked Thursday to trim as much as $100 billion from the stimulus legislation and clear the way for its passage as soon as today.

With the economy showing fresh signs of weakness Thursday, Obama said: “The time for talk is over. The time for action is now.”

But lawmakers faced criticism about aiding homebuyers — and not renters or those made homeless — as the recession worsens.

Sheila Crowley, president of the National Low Income Housing Coalition, questioned the decision to subsidize home purchases when housing prices still remain out of the reach for much of the working class.

“Why would we do something like this now?” Crowley said. “Really, only well-off people are in a position to buy a house.”

Buyers will still face tight lending standards, and mortgage rates have climbed since hitting a record low of 4.96 percent last month. The average rate on a 30-year fixed mortgage rose to 5.25 percent this week from 5.1 percent last week, mortgage finance company Freddie Mac said Thursday.