Commingling of funds (where you mix personal and business assets/cash) is something to avoid at all costs and the investor will probably require you to have a business bank account to wire the funds to or will give you a cashier's check made out to the business. You generally can't cash the check at most banks without a business account in that same name as is listed on the check.
Go onto the IRS website and you can apply and generally get a new employer identification number (EIN) within minutes online. Print that out, with a copy of your certificate or articles of incorporation/formation documents or good standing, resolution from the board or shareholders authorizing you to open a bank account on behalf of the company, and go to a local bank's business banker. I have generally been able to get them set up same day, especially if you do your personal banking there.
Now if you don't have a US banking relationship already and don't have a SSN or ITIN, you could either bring someone as treasurer in who does or you are right it may take a little while to accomplish. My advice is to do it right the first time and set one up right away.