Currently, they have around $290k and the number keeps growing every day, although it doesn't rise as quickly as the first few days of the campaign. however, there are still 23 days left and that's plenty of time to reach $600k.
To make it more interesting for backers, Lab Zero has added three more tiers of contribution to the campaign: Angel, Archangel and Divinity tier which costs $2500, $5000 and $7500 respectively. The $2500 "Angel" tier will include all of the $150 "Booster" set plus all of the custom prizes available on the $400 "Benefactor", $500 "patron" and $1000 "Patron Saint" tier which consists of a chance to work with the team to create a custom-palette for a character of your choice, a custom high-res piece of full-color digital art and having you or your own character inserted into one of the background in Skullgirls.
The $5000 "Archangel" tier offers the same thing plus a custom Foehammer fightstick designed by the Skullgirls team. While the $7500 "Divinity" tier also adds a paid trip to Evo 2013 to hang out with the Skullgirls team. These are pretty nifty rewards in my opinion and will only available in limited numbers so if you're interested, definitely go to their Indiegogo page and contribute!
Oh, they're also revealing more characters to vote for as the third DLC for every $20k contributed to the campaign so do check the Indiegogo page once in a while. Also, the PC version is on the works and you can get into the beta for the PC version if you contribute $30.
Oh, and for those of you who thought "$150k for a character? that's bullshit!" I ask you to check out this great article on GiantBomb written by Patrick Klepek before you say anything more.