Up to how many times may a preliminary hearing be 'continues'?

The most simple answer is you need to be talking to your attorney about this.  It is improper for another attorney to comment on a case where you are represented.  I will say from a legal standpoint there is no limit to how many times a case can be continued with the exception of runnning afoul of rule 600 which is your speedy trial rights.  Rule 600 states that you have 365 days to be brought to trial, less any time that you requested a continuance or failed to object to a CW continuance.  Your attorney should be on top of this.  District Courts usually have some arbitrary limit to how many times a case can be continued but if it is dismissed for this reason the CW will often refile the charges.  This does not stop the Rule 600 clock so keep in contact with your attorney and make sure they are reading you in on this issue.