The 41-year-old has enjoyed a long association with the Blues after initially joining the Academy set-up following his retirement from playing in 2007.
The former scrum half, who featured for Cardiff, Llanelli, Aberavon, Bristol Rugby, Pontypridd and Newport Gwent Dragons during his playing days, has also previously worked as Assistant Coach with Wales Under-20s and coached Wales 7s.
Director of Rugby Phil Davies said: "Gareth has been a fantastic servant to the Blues over the years. He has come from the Academy set-up, after Dai Young gave him a chance, and I've always valued his work ethic and professionalism, which is second to none.
"His enthusiasm for the game really is fantastic and he has a thirst for knowledge and to develop and get better. I know he will give everything over his remaining time with us.
"Gareth now has a wonderful opportunity, alongside his family, to go and work overseas and he will go with our very best wishes at the end of the year."
Baber will remain at Blues until the end of 2013 and insisted he still had much to achieve in the coming months.
He said: "I would like to thank everyone concerned with the Cardiff Blues, players and staff, but also pay a specific thanks to the fantastic fans who have gone through all the changes with the region and showed unwavering support.
"I started here as an Academy coach and have come through the Blues system into the senior environment and I would like to thank Peter Thomas and the board as well as Dai Young, Justin Burnell and Phil Davies for their roles in developing my skills over the last seven years here.
"Opportunities like the overseas role I will be taking up do not come along very often and I see it as a progression for me in terms of the job specification. It's a good challenge to add to my skills as a coach and I thank Cardiff Blues for their understanding and support with this.
"I am now focussed on the rest of the year at Blues and all we have still to achieve. We have a big European competition to look forward to and a clear focus to gain positive results in the RaboDirect PRO12.
"I truly believe the squad is progressing and evolving under the guidance of Phil Davies year on year and I'm sure the future is an exciting one for Cardiff Blues."
Richard Holland, Chief Executive, added: "We are sorry that Gareth will be leaving us, but he has a fantastic opportunity to develop his coaching career and we support his decision.
"Gareth has made a very positive contribution during his time with the Blues and the door will always be open for him to return in the future.
"Although Gareth will not leave until the end of the year, the search for the best possible replacement for him has started. Gareth will be part of that process alongside Phil Davies and we expect to attract candidates from home and abroad for this exciting and key role in the region."