Will you drive to work? if not, a place in mokotow near the metro may be good (espescially in about 3 years when the Rondo Onz metro stop opens).
A friend of mine lives in żoliborz on gwiaździsta - there is a huge amazing park across the street (including a 5 km path around the park). If you drive to work it may be a good place - if you drive down the street you can't miss it on the right, I think you would be about 6 km from the center.
personally I would live in the center, there are some parks behind Grzybowska, but they don't compare to the park on gwiaździsta.
There are no parks next to Grzybowska, some small green areas but that's it. Unless you mean Saski Park which is off of Królewska, and that's a nice one. When it comes to Mokotów, then it's a fine area, especially if you live close to Pola Mokotowskie, which indeed is a huge park!!! Rondo ONZ is really not that far away from there at all.z
Can you please suggest me good area to Live near Poleczki, Warsaw. Main concern is it should be in circle of 7-8KM with good access of public transport.