According to Forbes, 30 Rock‘s Tina Fey had the most income (gross earnings from shows, syndication deals, endorsements, etc.) among TV actresses in Hollywood during May 2010 to May 2011. Eva Longoria (Desperate Housewives) ranks second, and Marg, Mariska Hargitay (Law & Order: SVU) and Marcia Cross (Desperate Housewives) tie for the third place with an estimated $10 million each. Here is what the article says about Marg:
Helgenberg has anchored the original CSI on CBS for 11 years now. In that time much of the rest of the cast has rotated. She’s now acting opposite her third male lead: Ted Danson. The former Cheers actor took over from Laurence Fishburne, who had starred in the show for two and a half seasons.
Source: Forbes