You may need to reorder your network connections from the "Network" pref pane.
Just click here:
Captura de pantalla 2013-08-29 a la(s) 10.23.00.png 98.88KB
And put the Wi-Fi on top.
I have to do that every time I reset my network preferences, else the ethernet has a higher priority by default.
I have the same model and mine works with just this DSDT addition, no need to edit any kext:
Name (_ADR, Zero)
Name (_PRW, Package (0x02)
Method (_DSM, 4, NotSerialized)
Store (Package (0x0A)
0x6B, 0x10, 0x00, 0x00
DTGP (Arg0, Arg1, Arg2, Arg3, RefOf (Local0))