I would say a new bike- dedicated as a commuter or other "adventure" bike.
Like Blueberry said: you'll be asking the Ruby to do things she wasn't designed for.

I found a steel Bianchi Eros frame on eBay for less than $100 and built it up myself as a commuter. Stronger rims, wider tires, rack, fenders, drivetrain, lights, etc. I spent a little less than $700 building my tank. I LOVE it! Although it's heavier than my other bikes, I get good mileage on it, and it's rugged and durable and can take the abuse.
Now when I get on my 18 lb tri bike, I feel like I'm FLYING!

Never a bad thing to get another bike... (says one of the enablers).