Help please with new job wardrobe - casual clothes, still want to be stylish

[wentshopping]

I have just started a new job and want to update my work clothes - have been freelancing up till now so have casual or interview clothes, not much in between. Here are my requests:
Job is as a teacher assistant with children with special needs. I have to be on the floor, picking them up, running round the playground, helping them in the toilet etc.
I am allowed to wear jeans or even yoga pants.
I am v late 40s, and decidedly an apple shape.
I do not live in the UK - where I live (southern USA) it is hot nearly all year round, so in the winter I might throw on a cardigan. I do not get the chance to wear a coat or boots.
I do not love the things I find in the shops here, so I shop online - M&S, Boden sale, Gap for jeans, Banana Republic for blouses.
My work style up until now is ankle length pants (with a hint of stretch), floaty top ( to hide mum tum) and ballet flat-style slip on shoes. I can do heels up to 2". I would like to think that I can pull off a vaguely French-chic. The "locals" here wear fitness wear or tailored clothes when picking kids up from school.
Machine washable. Not to expensive. I would love to buy a complete Eileen Fisher wardrobe but its too pricey for me.
Any suggestions?

• not too expensive. Whoops.

Hi - I'd take your existing wardrobe and step it up a notch. I think you have to be in trousers given the physical aspects of your role - yes?

Have you looked at Ann Taylor? The sales are pretty good, and you might be able to find an outlet store near you too. Something like the cropped pants or relaxed ankle pants on here?

Top wise, I'd keep it fitted, again what you need to be able to do. So something like this

Thanks Closer. The trousers you have linked to are like ones I already have; I'm not really sure about a fitted top - I carry too much belly weight to feel comfortable in something fitted. If anything, that top looks a bit too formal - I would be expected to wear a school t shirt a couple of times a week. I was actually in an Ann Taylor outlet last weekend, and ended up with a skirt - a bit too formal for everyday though.
Any footwear ideas? - colleagues wear trainers.

I hope my last post didn't sound ungrateful - what I meant was that I think the pants you linked to are good, and I have some similar ones!