Hi dear,
About flat rent in Sana'a
The rent depending on the
1- Area that you like
Haddah area is costly , but If your budget good ,my it is not costly to you 
2- the type of the Flat
Ìý 2 roomsÌý you can find easily
go to map and have a look to Sana'a city
see the main street ,and where do you like to have a flat
Ìý
Just let me know when you be in Sana'a ,and I can help you
Thanks
Ìý Adel