、。
She's not bright, but she's got quite a nice body.
Literal
Head [contrast-は] bad [but-けど], quite good body is-doing [assertion-よ].
The double は is the key structural feature: the outer は marks 彼女 as topic, the inner は on 頭 is contrastive — 'as for her head (intelligence), it's bad, BUT...' implying the body is a different story. ~けど softens the contrast. なかなかいい is a casual compliment ('surprisingly good / quite good'). いい体してる is colloquial — the standard form would be いい体をしている, but dropping を and contracting ている to てる is natural in casual speech. The sentence-final よ adds mild assertion.