WiFi Card Upgrade for Inspiron 3721

Greetings from South Africa,

my trusted and reliable Inspiron is now over 5 years old. WiFi connection, however, is not great. The Wireless card 1704 only connects to 2.4 GHz channels. Is it possible to upgrade the card to access the 5 GHz channel of my home network? Which card could you recommend and where can I get it (in SA?)?

Many thanks