They are pregnant for around 63 days. The kitten's movements can be felt at about the 5th week, or35 days. if you have felt them for a week, she may be about 42 days. You may have at least 20 days left. she may be further along than that because the first movements are hardly noticeable. It's all a big waiting game, but just keep her calm and let nature take its course. Premature kittens have very little chance of survival. Make sure she is getting kitten food, it is higher in calories and nutrition. Especially when she is nursing.
They are usually moving around about 3 weeks before delivery. It's extremely hard to tell unless you know when she got pregnant. Then it's 63-70 days from that time. Premature kittens have almost no chance, so just observe her and it will happen when it is time!