Unfortunately Murali because of your choices, you're not going to see much of the Authentic Greece... you'll have a resort holiday at Porto Carras but it is entirely for tourists and nothing much Greek about it.
Also, in Athens in midweek, when you say you will be there, it is hard to find any kind of dancing/music venue that isn't specifically set up for tour groups. In the Monastiraki neighborhood there's a good taverna Cafe Avissinia that had traditional music on a sunday afternoon, & frequented by Greeks.
Also, a few years ago, an Athenian friend of mine came up with a tiny taverna - Kapnikarea Mezedopoulus, which is on Ermou Street near the tiny Byzantine church called Kapnikarea. It's lunch only (i.e, 1-5) Mon-Fri, live music. Here's review from 4-square
https://foursquare.com/v/καπνικαρέα-μεζεδοπωλείο/4e7f46d7a17c96ac9dd8b081
Here's a better one which I just found by doing a bit of "googling" (did you try that???) -- it's recommended for families, and has accordion music, traditional songs, and from the reviews, I guess that Guests are encouraged to dance! https://www.tripadvisor.com/ShowUserReviews-g189400-d6681127-r315251233-Akordeon-Athens_Attica.html
It may be just in evenings, have your hotel call to check.
For evening with music Cafe Kritiko in Plaka is well known http://www.paliatavernakritikou.gr/home_eng.html
Yes, there are tavernas that also have some performances of traditional dance but it's all put on for tour groups... men dancing in the military costume (fontanella), white skirts and pompom shoes (which Greek soldiers would never do!!), and lots of plate-smashing (which greeks never do!), and very expensive mediocre food/drink.
The best place actually to see traditional dance -- lots & lots of it!! is the Dora Stratou outdoor Dance Theatre, but unfortunately I belive its season ends in September.