2001 p0446 and p0420??? help

hello, I am very new to the prius world only one week! I had a beetle I traded the beetle and some cash for my prius! well first off i love love this car! it runs great but the ck engine light is on. I took it to auto zone and got the codes p0446 and p0420. the car has 182k miles on it. I took to to a local shop where the guy more or less told me to junk the car and with that many miles he said dont stick a penny into it. but I see ppl with posts on here with 300k miles and still going so now im second guessing his opinion of my prius! here in wisconsin we have the smog testing and it will not pass with the ck engine light on. I really cant afford to take it to a dealer and put $2000 dollars into it either . so my point is has anyone ever came acroos these codes and if so what was the problem. thanks so much in advance!!