First of all, welcome to the group.
To reiterate what others have mentioned, ED recovery is typically not an immediate thing, even with Viagra. Some are very fortunate and have erections as early as when the catheter is still in. Others never have an unassisted erection again, even with nerve-sparing surgery.
From what my urologist told me, what I have learned from the folks here and from what I have read in numerous web articles, here are some suggestions:
1. As biker Jim said, search for any ED-related threads here and read them. Lots of great information.
2. Try using the Viagra to stimulate blood flow, not just when you want to try sex, but a few times a week.
3. Consider supplements such as Vitimin B-50, Vitamin C, Vitamin E and L-Arginine.
4. Get a prescription from your urologist for a medically approved Vacuum Erectile Device (VED). Some insurance plans will pay for all or most of the cost.
5. Investigate penile injections...the most common being Caverject, bimix and trimix. There are many threads on this topic here at healingwell....and the men here who use them are more than happy to answer questions about their experience.
Best of luck to you, blue.