Even though you have a right to an attorney of your choice the judge might not allow you to change attorneys so close to trial. If you are allowed to do so then your attorney might ask for a continuation to prepare himself for the trial.
If you are having personality conflicts with your current counsel ask the judge if you can have him/her removed. You have to understand that just asking for the continuance does not guarantee you getting the continuance. But you need to address the conflicts with your attorney.
This is a very complicated situation. Colorado law certainly allows you to go forward with the attorney of your choice. However, if you attempt to terminate your current attorney at this late date, the court MAY rule that by doing so, you have waived your right to have an attorney represent you at trial.
You should address your concerns immediately with your attorney. If you have no resolution from that, ask that the attorney file an immediate motion to withdraw. If you wish to continue your trial date to retain another attorney, you will almost certainly have to waive your right to a speedy trial. This means that the 6 month clock in which the state has to bring your case to trial will start over again from the date you waive your speedy trial rights.
It should not effect your case. You have the right to fire and hire new counsel. Just be sure that your new attorney is willing to get involved at this point. The judge may force the new attorney to proceed as scheduled, even if he seeks a continuance. Most judges are understanding, but some may see this as a delay tactic by you, so be prepared to go forward on the scheduled date.