Thank you for your question. I look forward to working with you to provide you the information you are seeking for educational purposes only.
In order for them to justify charges in this new case, they have to prove they had probable cause
for the stop. This means they have to prove you were violating the law and that is why they stopped your vehicle. Once they prove that, then they have to prove they found the drugs legally. So they have to prove they had a legal reason to even look in your purse. If there was no weapon felt in your purse when they patted it down and you did not give them permission to search your purse, then the search can be challenged as unlawful and that would mean anything they found would have to be suppressed or thrown out.
Also, the relationship of the officer to your brother in law and your family, shows bias, which is a ground for destroying his credibility.
As far as the DUI charge, in order to use that for an enhancement, they have to prove the charge was valid and if you were in jail at the time, they could not validate that charge against you and as such that would cause the enhancement to be thrown out as well.
So based on what you have said, you have several grounds to challenge these charges through your attorney and you need to make sure you bring your new attorney all of the evidence supporting your contentions above, because if you present that in court
it can prevent the prosecution from proving their case beyond a reasonable doubt, which they have to do in order to convict you of anything.