No one knows for sure, but this article from the Columbus Dispatch in 2011 entitled, "Even recovered, ship's gold remains mystery" states:
"He said pending lawsuits are keeping Thompson from raising the money he needs to recover the rest of the gold, which some estimates put at 18 tons."
Its likely this is on the high end of estimates, but 18 tonnes at around $40 mil./tonne is approximately $700 M.. I don't know what percentage Odyssey would get. I'm guessing that since it was discovered by someone else, it will be around 50%-65% + expenses. It could be a massive haul. Some of the treasure is likely in coins which have Numismatic value. There is a youtube video from last year showing the chief scientist for the recovery talking at exhibition. The exhibition includes some coins. Look it up by its title:
SS Central America Chief Scientist Talks about the Ship of Gold Treasure