Do the lawyer need to be present at the preliminary hearing?

It depends on the contract you had and the terms of the representation he agreed to. If he was only retained for the bond hearing, but not the preliminary hearing, then he can asked to be relieved. If he was retained for all purposes or for the preliminary hearing (or however your arrangement was), then he must represent you unless relieved and allowed to get off the case by the court.

I'd suggest a phone call to your attorney to discuss what the issue is. Where you go from there depends on the terms of your retainer agreement. If you feel you're in the right and he was hired to represent you through the preliminary hearing, you can always pursue a complaint through the state bar association. Of course, that doesn't alleviate the underlying issue - you need a lawyer. If your current attorney refuses and is somehow off the case, you'll either need to hire another one or request a public defender if you cannot afford another lawyer.

The most important thing is protecting yourself in the criminal case. You can always pursue any action against your current lawyer, but don't let the criminal case go ignored.