、、、。
Um, I'm afraid I have a small matter to attend to, so I'll excuse myself here.
Literal
Um, I, regrettably [copula-です][but-が] small-matter [subject-が] humble-exist [because-ので], this area [at-で] humble-excuse-me.
Very polite keigo-level excuse. 小用 'small business, small matter' is a formal euphemism — can mean a minor errand or (colloquially) going to the restroom; context here is ambiguous but the very polite register suggests a social exit. 御座います is the very formal humble form of ある 'to exist/have.' 失礼致します 'I shall excuse myself' is the humble form combining 失礼 'rudeness (of leaving)' + 致す (humble する). Each element is elevated to near-maximum politeness.