23 year old, with a dog, looking for accomodation in Athens (or possibly roommates)

Hi, my name is Denise. I'm 23 years old and will be traveling to Athens at the end of July with my dog Nino.
I'm looking for something between 200 and 400 euros. As I will be bringing my dog it should be pet friendly. I would prefer something with a balcony if possible. I'm not very picky about the area but I would prefer something that is somewhat close to Kallithea (so maybe something in Dafni, Agios Dimitrios, Palaio Faliro, Pireas, Nikaia, Kerastini, Kypsali or Kolonaki). It really doesn't have to be a very big place nor does it have to be furnished (although an offen would be cool but not a must). The only thing I am a little picky about is that I would like something that's not on the ground floor. But I think the most important thing for me is that it's pet friendly.