The Senate reached a deal on saving the dwindling "cash for clunkers" program late Wednesday, agreeing to vote on a plan that would add $2 billion to the popular rebate program and give car shoppers until September to trade in their gas-guzzlers for a new ride.

The program offers car buyers rebates of between $3,500 and $4,500 for trading in their gas-guzzlers for new, higher-mileage models.

Following lengthy negotiations, Senate Majority Leader Harry Reid said Democrats and Republicans had agreed to vote on the plan Thursday, along with a series of potential changes to the bill, which was passed by the House last week. Reid has said Democrats have enough votes to approve the measure and reject any changes that would cause an interruption in the rebates.

Reid said the agreement "accomplishes what we need to accomplish."

Late Wednesday, it was not clear that any of the proposed amendments stood a chance of passing. Some of them included placing an income limit on those benefiting from the vouchers and requiring the government to sell off its stakes in General Motors Co. and Chrysler Group LLC.

The government said Wednesday that more than $775 million of the $1 billion fund had been spent, accounting for nearly 185,000 new vehicles sold. President Barack Obama has said the program would go broke by Friday if not replenished by Congress.

The new funding would triple the cost of $1 billion rebate program and give as many as a half-million more Americans the chance to grab the new car incentives through September.

Car companies have credited the clunkers program with driving up sales in late July. Most consumers are buying smaller, more fuel-efficient vehicles under the program, according to a list of the top-10 selling cars released Wednesday by the National Highway Traffic Safety Administration.

Among manufacturers, General Motors Co. had the largest share, accounting for 18.7 percent of new sales, followed by Toyota Motor Corp. with 17.9 percent. Ford Motor Co. was third with 16 percent of the sales. Detroit automakers represented 45.3 percent of the total sales while Japan's Toyota, Honda Motor Co. and Nissan Motor Co. accounted for 36.5 percent.

The Toyota Corolla is the top-selling vehicle on the list, followed by the Ford Focus, Honda Civic, Toyota Prius and the Toyota Camry. There is one SUV on the list, the Ford Escape, which also comes in a hybrid model. Six of the top-10 selling vehicles are built by foreign manufacturers, but most are built in North America.

Senate passage would send the legislation to the White House for Obama's signature and assure consumers there will be no interruption in the program that has led to packed car dealerships nationwide.

The deals are aimed at boosting auto sales, which have been at their lowest levels in two decades.