Is it time for a new hv battery?

The dreaded Red Triangle showed up the other day. Prius has been driving funny. Revving high, not wanting to go when I step on the gas, today the brake light came on randomly and I had to pull over and restart it to get it to stop beeping at me. It's a 2006 with 211k on it. Error codes today read P0A80, P013, P3014. I know the first is for the battery pack. Is there something that I should look into first before the battery? Are the batteries pretty simple to DIY? I've watched a couple of videos and it seems straight forward. Luckily there is a place in town that has handles batteries.

Thanks for all of your help!