Dear if you fix it or buy a new laptop will go expensive to you. i think you should buy a booster like wilson amplifier  
Hi I purchased a Dell Inspiron 15R at the last week and I am having problems with the WiFi signal is  EXTREMELY Weak and is only working just beside the router, the router is only 2 month old so is fine with any laptop. Try to  increase the  wireless performanc in the laptop still not work . Now am looking for help. thank
WiFi Signal Is EXTREMELY Weak