FARMINGDALE - Federal student Stafford loans are at the center of an election year battle, as loan interest rates are expected to double if Congress doesn't act by July.It's a scary deadline for more than 7 million college students across the country, who will have to pay 6.8 percent interest rates on government-subsidized loans if Congress doesn't pass legislation to prevent it. The current rate is 3.4 percent, but keeping rates low could come with a cost.The Republican-controlled House passed a bill today that provides $6 billion to maintain low interest rates for student loans by slashing funds from President Obama's health care law.The bill will now go to the Democrat-controlled Senate where it's expected to die. If it doesn't, the president has vowed to veto it.