So I've had this MacBook for about 5 years now, all is working extremely fine except for WiFi which started yo craps out on me. I literally have 25 different WiFi signal around my house. But my MacBook is only showing one out of twenty five and its showing the one thats not mine. Every other device i pull out shows all those 25 even the weakest N9 shows 20 of them. Now this started to happen since last Friday, since then i have reset pram, smc, let the battery drain for complete two days and complete recharge, taken to different places where it absolutely shows no WiFi in range where other devices shows. And it was just working great until last week i decided to restart to no apparent reason, ever since then its only showing one available WiFi. I also deleted the location and created new one, deleted the system configuration folder also, all in all i created a partition and installed fresh snow leopard and even on fresh installed partition all i can see is one WiFi which i debt have access too. Matter of fact, i am using my n9 to ask about this in here since i cant use my laptop. I do have ordered an external WiFi but i would like to know if there is anything else i can do to get this WiFi working, i know its not the airport card coz if it was then i would not even see this one visible WiFi and it started this behaviour only after a simple restart.
so any insights and help from you guys would help until i get my bewildered external WiFi antenna.

btw kismac with active mode also shows only this one WiFi but has about 7 with passive mode without any ssid information.