As per now (October 2012) the planning of Silom Line BTS Extension is to start as below.
Taksin – Phet Kasem Extension
S9 Pho Nimit To be opened on mid of January 2013
S10 Talat Phlu To be opened on mid of January 2013
S11 Wutthakat To be opened on 12 August 2013
S12 Bang Wa To be opened on 12 August 2013