Target have some really lovely stuff in a range of sizes, reasonable prices, and you don't have to dress like a nana! But don't limit yourself to one place. Maybe hit Target or SG for some basics, like slimline tops or wrap cardigans, and get your feature pieces from other places, like maybe some silk wrap skirts from Ishka or Tree of Life or even markets.
My style is "Op Shop Opulent" so maybe you don't want to take my advice though

ETA: I borrowed some Trinny and Susannah from the library, found it really really handy.