It's a tough thing to do... writing while at the same time holding down a full-time job (made more tough like by also rearing a baby). However, there is light before the dawn and dusk before the bonny doon...
Whatever, there's is reason to believe it can be done, and well.
The May 2006 issue of Fast Company Magazine contains "Join the Corporate Literati" about people who have succeeded (and continue to) at this dual effort. Another story from Fast Company in Jan 2006, "In Good Company" is about Australian author Max Barry who wrote his first novel during lunch breaks away from Hewlett-Packard. There are of course many ways to skin a cat, but in Barry's case, he utilized the Internet Writers Workshop to improve his craft.
I can attest that Barry's most recently published book, "Company" was an excellent read with a very funny (of the biting humor variety) look at Corporate America and it's follies.
So, all this being said, the point of the story is is someone wants to write, they will. It may be tough and may require disciple, but it can be done. That's encouraging.