。
I'll bring it over to you tomorrow.
Literal
Tomorrow there [to-へ] hold humbly-go.
持ってまいります combines the te-form of 持つ ('hold/carry') with 参る (humble for 行く/来る). The compound 持って参る means 'take [something] with me, humbly.' そちら is a polite 'there/your side.' The へ marks direction. A highly deferential delivery commitment, typical of business language.