As sad as I am to leave, I have no choice. I rented a nice studio apartment in Copacabana for a month, but now have to leave after only staying for 3 weeks. It has air conditioning, cable tv, digital safe, etc.... It is located in a good area (Miquel Lemos and Xavier Silver), close to the beach, bars, and many restaurants, etc...
It is available July 10th (morning) until the 17th, and for these days, it can be rented for R$50 a night. You may be able to rent it for longer, but you will have to check the availability with the owner. (I have it rented until the 17th, so I can guarantee that week is still available.)
If interested, email me at brentsmyth1982 at yahoo com and I can pass along the information.