How do I make my macbook pro (2011, OS10.7.5) reconnect to the network when the signal goes down?
Are you sure it's Wifi outages and not a DNS server problem? If you've been using Safari, check with other browsers – if they get through while Safari doesn't, set OS X to use an alternative DNS server (System Preferences > Network > Advanced…), e.g. OpenNIC.org, OpenDNS.com