Why are you trying to change your MAC address if you are connecting to your home network just to browse the net?
Anyhow this is the way i do it. I dont use any of the programs i just do it all through the command line.
First delete the contents of /etc/dhcpcd
next open up a konsole window and do this..
My command looks like this
iwconfig <interface> essid <name of wireless network> key <wep key>
IF YOU USE WPA THIS METHOD WILL NOT WORK. YOU MUST USE WPA_SUPPLICANT!
iwconfig ath0 essid 16226 key 14:28:42:56:70:84:98:AF:BE:CD:10:20:33
after you enter the information for you home network finish up with the command...
Mine looks like this
When that completes KNemo will pop up a tooltip saying that your interface is connected.
best of luck