How to set the metric on wireless cards for priority and also how to parse the signal
 

I am doing a project on handover in wlan network,
I have installed two wireless cards on my laptop and I want to write a bash file that will control the two wireless cards.

So what I want is first to be able to check the signal strenght level in the wireless interface card if it is less or equal to a certain level that will be set by me and also I want to check for the number of packest dropped to trigger the handover.

So what will happen, the secondary wireless card (The one that is not associated with any access point will start scanning the network and will associate to an access point with better signal and the primary wireless card (The one that was communicating or associated)will be disconnected and will start scanning also, so as you can see the role will be swapped

So I want to be able to extract or parse the value of the signal strenght level recieved by the wireless card and the number of packets dropped so i will be able to trigger the handover

I am new in bash programming and C programmming and know java and C#

Thanks for your help