car wont accelerate once i get to 65 mph

It sounds like your transmission isn't going into the 4th or 5th gear.I would check your trans fluid and look at the color,if bright red ,almost pink,trans isn't burning up,if the color is brownish and smelling like it is burnt,than you could have a trans problem.But definately get it looked at by a good trans shop in your area.

Can you describe you problem with a little more detail? Is your car free revving up to 4 or 5 thousand RPM or is your cars RPMs stuck very low when you reach 65 MPH. If your car is free Revving then it is like rachel said, more then likely your transmission if your car is very doggish and will not Rev past about 1500 RPM it is something to due with your Fuel or Ignition. Try to narrow it down a little bit and you should be able to pin point what your issue it. Hope this put you in the right direction.

any engine light on the dash?...And if so a computer is the fastest answer to your problem.

possible mass air flow sensor, cat convertor, trans, fuel related - have a diagnostic code scan performed - with a pro that can read the data properly - may shed some light on the problem..