Brandon, congrats on the first purchase! If you bought a condo on the Red Mountain (upscale Highland Park) or Homewood, you probably made a pretty timely purchase. My advice would be to avoid a personal line of credit if at all possible due to the rates and I'm not sure you'd qualify without a strong credit score (not accounting for any personal relationships you may already have in place).
If you plan to live there for a year, my advice would be to (1) do a market comparison of other similar condos being rented and determine whether the $15,000 will be worth the potential higher rent or if the rental market is capped, (2) see if you can put some sweat equity into the condo first before spending that sum, and (3) take out a credit card and start building credit ASAP! Dave Ramsey is great for where you were, but not for where you are going! You need to build credit now by responsible use of a credit card.
For the business expense piece, start saving all receipts for renovation purchases, etc. When you eventually move the condo to an LLC, you will be able to use deductions without messing up your standard deduction. CPAs are a great resource--I would recommend buying one lunch to discuss this informally. They generally won't charge anything if you buy them a $25 lunch.