。
The problem is that we're short on money.
Literal
Problem [topic-は] we [subj-が] money-shortage [copula-である] [quotative-という] thing [copula-です].
Functionally identical to a common variant using 私達 (kanji) — this version spells 私たち in kana, somewhat more common in modern writing. である is the formal/written copula, and the whole clause is framed by ということです.