Apartment to rent end of July

I am looking for an apartment to rent, (perhaps a large one bedroom with pullout sofa) for my Berlin cousins, both working professionals.

They have 3 small children, two 5 and 7 year old little girls, and a 10 month old, and want to stay near me on the UES from July 27 to July 31. Thus, we are looking for an accommodation on the Upper East Side only. They are willing to pay $2,000.00. The Airbnbs here are way too expensive. I have tried and looked into the UES hotels too.

Also, would anyone have a stroller to borrow for those few days?

I am the Yorkville/Kleindeutschland Historian, president of the 52-year-old East 83/84th Street Block Association (16 blocks from 2nd to 5th Ave.) and VP of the 19th Precinct Community Council.

I would be grateful if you could help me.