。
I'd like to make a deposit.
Literal
Deposit do-want-[explanatory-のです]-but.
預金 ('deposit / savings') + する forms the suru-verb 'to make a deposit.' The desiderative ~たい combines with the trailing のですが opener to make a polite, hedged request — 'I'd like to..., if that's all right.' Typical bank-counter vocabulary in Japan.