。
She poured all the love she could into her children.
Literal
She [topic-は] [as much as possible-genitive-できる限りの] love [object-を] children [to-に] poured.
できる限りの uses the same 'as much as possible' frame, but with の attaching it as a noun-modifier — できる限りの愛情 ('all the love she could (muster)'). 注ぐ ('pour') is used both literally (注ぐ for water, drinks) and metaphorically — 愛情を注ぐ ('pour love'), 注意を注ぐ ('pour attention'), 心血を注ぐ ('pour heart and blood (into something)'). The dative に on 子供達 marks the recipients of the pouring.