Sensor help needed

Hello all, I'm in desperate need of help to avoid getting my eyes poked out by mechanics.I don't know alot under the hood BUT I'm trying!

I've recently purchased my first 4Runner, 1999 2.7 V4. Took to AutoZone for diagnostics and codes pulled were P0141 HO2S bank 1 sensor 2 heater circuit malfunction. P0402 Excessive EGR flow detected. I was told downstream o2 sensor and EGR valve.

Okay, well I go to meineke and was told upstream o2 sensor for $275 for sensor and $75 labor. V/C gasket for $98 $26 grommets and $285 labor for that.

I JUST WANT TO BUY THE CORRECT PARTS ONLINE. Our family mechanic works on my fathers 00 Sequoia so I trust him.What I really need is the exact parts to buy. Denso, a link would be perfect!1999 Toyota 4Runner 2.7 automatic not sure what else to include. On the sticker under the hood it reads SFI EGR HO2S(2) TWC 2.7

Thank you in advance to anyone who takes time to help a girl out with this. Cheers