I am not sure I am adding anything new, but here goes anyway ...
There are three different issues here:
1. You need some time to your self.
2. Your daughter needs to listen to your directions (discipline); and you need to decide when to pick your battles.
3. Does she really need a nap, and are you nagging her?
Yes, you need time to yourself (we all do). It sounds like you might be nagging, and that she may not need a nap.
So, you cannot force someone to sleep, but you can require her to stay in her room, or a particular space. However, you are going to have to "fight" this to establish this rule. 3-4 years olds are testing limits and testing their independence -- that's life.
We have very few rules in my house -- probably too few, but one firm rule that both my children know, and do not fight with me about is: "go to your room." My kids are 10 and 5 and it took work on my part to teach them this, and that disobeying this comand was going to result in something they didn't like. Throwing away a favorite toy, lose of TV or computer time, cancelling a play date -- serious stuff. I had this rule down when they were little and it is the best thing I have ever done.
I picked this one rule to make a stand about because of advice from my Mom, who had five children. She told me that I need to teach them this when they were little, if I was going to every dream of being able to send them to their room when they are teenagers. She also said I needed to pick one or two things, to make firm rules, so that I could establish my authority when they were little, or I would have way too little influence when they are teenagers. I don't know yet if she was right, but it certainly worked for her, so I am giving it a try.
I hope this helps.