Hi Lorraine,
I will delete your email address from your post, since this is a public forum and you probably don’t want spambots harvesting your email.
Regarding your question, there are no built-in reports. However, you can export all the sign-up sheet data to a CSV file and then use something Excel to filter and create reports for you. You would just want to make sure that you do NOT have the option set to delete expired sign-ups if you want to retain a history of everything that a person has signed up for. If you have access to PhpMyAdmin, or similar database tool, from your hosting control panel, you could also just export the signups table directly to CSV and sort through that with something like Excel.
Otherwise, at this time there are no time tracking features or detailed volunteer reports built-in. You could always add that to the Feature Requests section.