First, are you sure it is migraines? I.e. do you have a diagnosis/history of migraines? If not, you really really need to see a doctor right away. Migraines, while horrible, are not particularly hazardous to your long term health. Other kinds of headaches can be indicative of various dangerous underlying causes.
If you know it is migraines, there isn't much better than Excedrin for over the counter drugs. Anything good requires a prescription. Some people find just straight caffeine is helpful. You could also try Sudafed, but don't mix that with the Excedrin. Try to avoid your triggers, obviously.