Upvote:7
Yes, you can apply for a B1/B2 visa (or for that matter, any other visa) whilst you hold an ESTA. In general this would not be required as a ESTA/VWP gives you basically the same status as a B1/B2, however the reason you've stated is one of the few differences - VWP is only valid for 3 months, whilst a B1/B2 can allow you to stay longer (normally up to 6 months).
Given that your ESTA was approved despite your arrest, and given that you were not convicted, it is unlikely it will have any impact on your Visa application - however you will need to provide details of the arrest, and it is possible that your application will be delayed as a result. I would suggest taking as much evidence of your record as possible, especially documents showing the dismissal of the charges.