From a quick visual check:
Note that I didn't do a detailed comparison (didn't check letter spacing in particular); those are just what comes to my mind and seem relatively similar. If you are looking for specific font features / characteristics, please specify them.
I would use "Ubuntu" to replace the "NeoSans".
To replace "Fago" I would use "Aller".
They’re both designed by The Dalton Maag Font Foundrie.
The first one, "Ubuntu", is free to use and you can download it from http://www.google.com/fonts/.
The second one is free, but only up to 25 users, and you can download it here: http://www.daltonmaag.com/buyonline/sans/aller.