。
All she could do at the news was cry and cry.
Literal
She [topic-は] that news [object-を] hearing [then-て] just-just cry [only-ばかり] was.
ただただ (the reduplicated ただ) intensifies 'nothing but, just and only' — pure absorption in the single action of crying with no room for anything else. であった is the formal-literary past of だ, slightly stiffer than だった. Together the doubled adverb and the formal copula give a weighty, somber tone — the kind of phrasing you'd expect in elegiac fiction or a measured personal account. Reduplication for emphasis is a productive Japanese device: 重ね重ね ('again and again'), 度々 ('repeatedly'), 着々 ('steadily').