If you had said radio-quality, it's traditionally about a month of work to make a radio-quality production of one song. That's usually divided among the various musicians and engineers, so maybe it's something like seven people working for three days. For an album of 12 songs as a rule of thumb you figure a year of work or $100,000, or actually somewhat less since you're doing a significant part of the work yourself.
But you said "like professional quality" and that makes me suspicious. If you just want CD-quality sound you can get that with a $50 microphone plugged into an iMac ($1000) with GarageBand (included). I'm not exaggerating; the top-of-the-line equipment sounds slightly better but you will probably not notice the difference unless you're listening on at least a $500 pair of speakers. The reason to pay more is not for better sound quality but for the polish and attention to detail that makes the record sound better than any of the musicians on it. For that you have to go by the producer's track record, i.e., she's done albums that sound just like the album you want to make . . . and then you have to trust her to do the same quality of work for you.
You didn't say how many songs would be on this record but if it's just one song then $15,000 is probably a little high, even for a producer whose name is on a dozen albums you have in your collection, but worth it if this is the one producer in the world who can do the record you want. On the other hand, if it's 15 songs at $1,000 per song you are not paying nearly enough to get the kind of polished production that will get people's attention. Yet it might be the right thing -- producers, like musicians, don't get paid what they're worth until they're famous.
If you aren't sure you can get a polished production with the budget you have, and you have time to spend, you can at least attempt to do your own production. It can take months if you're doing it in your spare time, but as I said, the sound quality can be just as good as what you hear on anyone else's record. If you want to sell records to your fans, I don't think there is any use for a middle-quality recording (i.e. high sound quality, but only a little bit of polish). Do something that "sounds like you" and your fans will like it. The next step up should be "radio-quality" and you have to recognize that that's a lot of work, and it's not just a matter of expensive equipment and perfect sound quality. I don't think it makes any sense in most cases to spend a lot of money for anything in between "sounds like you" and "radio quality".