What equipment (brand, model, etc) do you recommend I need to get?

After ATT installed the fiber network, I was having trouble hooking up to 5G. After researching, I find that my wireless card is a Ralink 802.11 bgn which, I am told does not support 5G. So, I am looking at adapters to fix. My question is, does ATT sell these? And, if not, can you recommend one? It all seems very confusing to me. I sure would appreciate any help and/or advice you can give. Thank-you