I almost agree with Poli about "quisieras", but this subjunctive is used for reasons of courtesy.
All of your proposals are correct. "Concertar" is a very formal verb though.
The ones you'll hear in Mexico are with "programar" and "agendar". And we prefer "usted" instead of "tú" (so, "quiere"/"quisiera"/"querría"), unless the relationship between the service provider and the patient is very relaxed.
If the patient is the one talking, they might rather say "quiero sacar una cita". Don't ask me why, but "sacar (una) cita" is the most commonly heard expression around here. "Sacar" is quite a handy verb.