I know how you feel! I just went on a venting rage about this about a month ago. This is also why we are only having one..(hubby getting fixed in a month). It is VERY hard to find time to ourself. I have found that DS, 3 months old, will only entertain himself for 15-20 minutes. To be honest, I found that I will not have any time to myself until after DS goes to bed. I stay up until about 1AM...I clean the house, do my nails, get a long, hot shower, what ever. It is the BEST time for me.
You may want to try and put her in front of the t.V and play a DVD. My DS is only 3 months, but he LOVES the Baby Einstein videos. He can stare at the T.V for quite a while. I have just resigned myself to the fact that right now DS is VERY needy and after about 3-4 months I will be missing that so it does not bother me too much

(They grow TOO fast for me!)