Database app, accessible from Mac, iPad and Web
Short answer, grab FileMaker Pro. The iPad app integrates nicely with the desktop, and it runs on both Windows and Mac.

Additionally, since you are comfortable with HTML, CSS, and VBA, you might want to try NSB/AppStudio, which can use PhoneGap to generate a native iOS or Android app. We've created several apps to be deployed in the field for such things as product catalogs, quality checklists, etc. and it works pretty well.