Rent of apartments in Ukraine (Kiev, Lviv, Ivano-Frankivsk)

From December 20 to January 1, I will travel in Ukraine. I will be in Kiev, Lviv and Ivano-Frankivsk. I like this country where I have already been two times. I am looking for small apartments to rent in this cities for a couple of days. Does anybody has an apartment to rent to me or can suggest me a reasonnable priced rent agency?

Many thanks in advance for your sugesstions