"I write excellent product specs" -- are these product specifications sufficiently detailed to have a consulting Software Quality Assurance person be able to test each feature of the product? Sufficiently detailed so the multiple people you hire can seamlessly do integration testing? What scaffolding do you provide for each of the developers? Do you have the same "source control" of your specifications as you do for the code generated from them? How do you handle "feature creep"?
"Bug tracking and source control" -- Do you have staff or contractors who confirm the bugs? And how do you handle regression testing during development and subsequent maintenance? How about code reviews? Who handles customer service queries?
"Empathy for developers" -- demanding bug-free code without the tools and processes to give the contract developers a fighting chance? How well do you anticipate corner cases in your products, so you can include them in your specification? What practices do you insist on to catch bugs early in the product development cycle?
"...hire someone full-time...know a lot of languages and be proficient in all of them...can't afford to pay someone $100k/year" -- Sounds like a version of the Universal Specification: "I want everything, now for, $1.98." As for pay, that one is easy: make him a partner, and he earns from the bottom line just like you do. You will probably have to take a bit of a pay cut to attract what is essentially a do-everything maintenance programmer, not exactly the career track that anyone with the type of experience you are looking for would choose. Have you looked at the pool of experienced programmers? There are quite a few who have been put out to pasture because they don't have the "zing" in their resume that most [In]Homan Resource people look for. Learning languages is a skill easily picked up. Learning how to un-muddle code written my others is an art, and people skilled in the art of decoding a mess are much harder to find, let alone identify.
Transition? One possibility is to find a contractor highly skilled in maintenance programms. If he works out, offer him a partnership.
As for the attitude that any piece of software can be completely bug-free: that's a holy grail. The ADA Programming Language was invented to try to provide an underpinning to achieving the holy grail -- when was the last time you heard about it seriously? Several research-based languages have been developed that purport to "prove" that they are correct...but watch what happens when an unanticipated corner case hits the code. Many of the advances in languages and compilers focus on finding easy and trivial problems quickly, so a programmer doesn't have to spend time finding and fixing them. (Scripting languages, particularly those that compile "on the fly" such as TCL and most shell scripts, point out the advantage of a proper compilable language; you lose some flexibility, but the overall programmer cost is far lower than tripping over mistakes one at a time, particularly if the programs run are measured in minutes and hours.)
Your business model will need to change. Count on it.