Read my hub on Gingko and cold feet you'll get some information on treating blood circulation problems that also affect the male erection.
I would recommend you do the following:
(1) Live an active lifestyle taking up physical activity.
(2) eat healthy foods low in oil as oil can effect blood circulation important in erections.
(3) Take regular dose of Gingko, Saw Palmetto with Vitamins A,C,E, selenium and Zinc.
You may also consider taking Korean Ginsing - give it a few weeks and you'll notice the difference.