The reason why Showtime/M-1 didn't advertise the show properly, was because some the Russians on the main card didn't have their visas issued until few days before the fight, so they were concerned about promoting a card with names that would possibly not be able to make on the card, and they didn't want to take that risk.
I don't think the numbers were bad at all, specially if you compare to Bellator (which was a little above 150.000 and had much more time to advertise, not count out the fact that Bellator has a bigger name in the US). Showtime only had announced the event on their schedule, but they didn't do one single commercial for it. M-1's only source of media was the internet. I heard that all the visa situation for the Russian guys is taken care of for the rest of the year, so I'm sure there will be a better advertisement from Showtime/M-1 for their next card (july 8th) , so the rates will probably be higher, specially after this first show , which was considered a success by Showtime/M-1 and by the fans, which is even more important.