My mother comes to stay at our house at least once a month.
Literal
Mother [topic-は] month [per-に] once [topic-は] home [to-へ] stay-[purpose-に] come-[benefactive-polite-てくれます]
へ instead of に for the destination. Both are natural with motion verbs; へ slightly emphasizes the direction, に slightly emphasizes the arrival point, but for a destination like 我が家, the difference is usually felt as register or cadence rather than meaning.