I understand that 25 mg 2x is the maximum dosage of coreg (carvedilol). if correct and my ejection fraction decreases what alternative medications are available?

Depends: If you are taking Carvedilol for low systolic function, low ef, then you should be on other meds, e.g. Ace-i or arb as well. Depending on how low your ef is, you may need to be on others meds too. If your heart rate is not at goal with carvedilol, your physician may try you on other beta blockers. Cause of low ef should be investigated and treated as well.

Options available: I rarely use more than Coreg (carvedilol) 25mg twice a day, but doses uptown 50mg twice a day for body weight >85kg are permitted, if heart rate and BP tolerate. I would start on spironolactone or eplerenone, which are proven medications to improve heart function, provided kidney function/potassium levels are acceptable. Use of biv icd is another option. Discuss with your cardiologist.