i heard the filming is to be done by end of december i assume the rest is the visual stuff, having paying attention to the gag reel of avengers *noticing how a scene with captian and iron man together wasnt present when chris evans was acting the line*

assuming it isnt explosive cgi detail should take no longer then 2 months max at the most so a may release is possible i dont think a march is though unless they got really lucky

In reply to your other comment, after watching the gag reel isn't it amazing how much of each scene was so fake? I was amazed by it. I knew a lot of things were added in, but there were scenes where Downey Jr was walking in front of massive green screens that I thought were actual sets lol

yeah like "jarvis dont ever talk to me again once im off screen* or "dudes your on your own* lol