Stafford loans are subject to annual and lifetime loan limits. For fourth-year students, the annual Stafford loan limit
is $7,500 ($5,500 subsidized/$2,000 unsubsidized) for dependent students. Depending on your situation, your school may be able to increase loan amounts, providing you haven't already hit your limits.
If you have maxed out these loans (or do not qualify for the need-based subsidized loans), you will need to find funding elsewhere, such as a private student loan or scholarship.
If you obtain your bachelor's degree, and want to go back for an associates, there are limited resources for this. Federal grants (such as the Pell or SMART Grants) are not available to bachelor's degree holders, and Stafford loans are subject to undergraduate loan limits as mentioned above. To become eligible for more funding, typically students must move on to receive their master's or a Ph.D.
For more information, I'd suggest contacting your school's financial aid office.