Find postal addresses for 250 names

I am hosting an event in October and have compiled a list of 250 invitees, but I don't have their addresses. I am looking for someone who can go through the list, and get their company/office address online and input into a spreadsheet which can then can be used for a mail merge. The invitees are professionals with most of them being company owners. Their addresses will be publically available online.

In terms of deadlines, I need the full list by Monday 9th September at the latest.