Manually importing webforms and data with mysql... where is it now?
Webforms are nodes, so you'll also need to bring the node (and potentially field and other depending on your site's configuration) data across.

Make sure the node ids for the webforms are the same as they were in the original site, or you'll have to do some manual work to get the data linked back up again.

This is why it's arguably better to migrate content, rather than do a raw data export/import, as it gives you the opportunity to massage/prepare data as required for the new system.