Edit: Thanks to JamesPi we know now that is it Shaelyn Cado Killam!

Unfortunately nobody has released the name of her daughter yet =( but according to a user here the initials of the baby are S.C. Killam =D

Her daughter is called Shaelyn Cado Killam she was born on 16th May but they kept her a secret until now no further information has been released.

This an article about Cobie:
Smulders Welcomes Baby Girl
Friday July 3, 2009

Welcomes Baby Girl ShareThisHow I Met Your Mother actress Cobie Smulders has given birth to her first child, Usmagazine.com has confirmed.

The actress and her fiance Taran Killam, both 27, welcomed Shaelyn Cado Killam on May 16, a rep for Smulders tells Us. Shaelyn is the couple's first child.

Smulders, who announced her pregnancy in November, stars on the CBS series as Robin Scherbatsky, a reporter who has vowed not to have kids. Killam appears as Blauman, a former coworker of Neil Patrick Harris' character Barney.

Baby blabber has been the talk of the HIMYM set this year. The show's cocreator, Craig Thomas, joked to TV Guide about his fertile workplace in November after both Smulders and Hannigan announced they were expecting. Hannigan welcomed a daughter -- her first -- in March on her 35th birthday.

"If you're trying to start a family, please come visit the set of How I Met Your Mother," Thomas told the magazine. "Just come by and hang out for a day or two. We can't legally guarantee anything, but by the time you leave, you will almost certainly be pregnant."