You need a crisis! not that I'm wishing one on you, but there is nothing quite like a purring cat's fur to cry into, and it's SOOOO much better when thety can go out, even mine (Lucy strangely enough!) gets on my t*ts when she's under my feet mithering, and I love her to bits!!
Oh no, I didn't mean I thought you would take her back. What I meant was, in a rescue centre the staff don't have the time to spend with every cat, the cats don't have much space or freedom, and although they're not neglected, they don't get as much human contact as they need. Now she's got you, she's making up for lost time and getting all the affection she can before someone takes it away - she doesn't know yet that it's not going to be taken away from her.
Once she's settled in and able to go outside, she will probably be less clingy, and will certainly be under your feet less.
She will be able to go to the loo outside soon though won't she? I wouldn't care for the litter tray bit either - enough clearing up to do without that. Does she sit on you? That in itself can be a bit annoying but it is also a lovely time to bond with your pet. The stroking is very therapeutic you know.