。、。
Cut it out already. Keiko doesn't like it, you know.
Literal
Sufficient-enough do [casual-っつの]. Keiko-san, is-disliking [conjectural-だろ].
A firm casual rebuke. いい加減 is an adjective/adverb meaning 'moderate, reasonable' but in いい加減にしろ it functions as 'that's enough,' 'cut it out,' 'you're going overboard' — literally 'do it to a reasonable degree.' A common fixed expression for telling someone to stop their nonsense. っつの is a casual/emphatic sentence-ending contraction of というの or とよ — marking the speaker's exasperation and expectation that the listener should already know. 嫌がる ('to show dislike,' 'to display displeasure') is distinct from 嫌い ('to dislike') — 嫌がる is an external expression of displeasure, observable behavior, while 嫌い is an internal state. ~ている form marks the ongoing display.