"I have heard i shouldn't let her cry for longer than a few minutes "
Again, this is one of those topics where you will get as many different answers as people you ask. I ended up letting my oldest cry herself to sleep out of sheer self-defence, even though I felt rotten doing it. If I cuddled her to sleep, she'd wake the minute I put her down and start crying through overtiredness all over again.
Because a baby is crying does not always mean that anything is wrong with them, sometimes babies just cry! It's one of their primary means of expression. (I'm sure that someone will disagree with me here, and you are welcome to My kids are both well-adjusted, emotionally secure individuals.)

Is it an issue if she stays awake all day? A solid 9 hour sleep at night is something to be treasured, if she naps during the day will it interfere with this? Every child's sleep patterns are different.
If you need her to rest during the day, it will not harm your baby if you put her in a room with some soft music playing, maybe looking out the window, and leave her wrapped safely in a cot for some quiet time while you get a sleep or housework out of the way. Babies really don't need to be entertained 24/7, it's just that with the first one we think we have to or we are being negligent Mums!

Work out what suits you, at this age babies CAN be trained into a pattern of naps during the day if you persevere, you just need to decide how you want to do it.

Kerrie