Back to work on Monday... wardrobe updates?

[60sname]

I'm returning from a year's mat leave next week, and was hoping for a few tips to update my work wardrobe.

It's business casual, in the city but sadly no big budget. I like simple lines, slightly trendy but nothing too high-fashion as I'm trying for capsule wardrobe for both time and budget reasons. I like dresses but don't wear them hugely often as the air con is freezing! I am 33.

Photo of current clothes/shape (pre-ironing but you get the idea )