Eric,
Am I correct in assuming that I can not add DCS unless I buy and Ipad.
No, that's not quite right. 
You can purchase a DCS set including a DCS WIU and TIU for use with any Apple or Android, smartphone or tablet (including a Kindle Fire). You would then download the free DCS App and use it on one of the aforementioned devices, either in its free or upgraded (for $) versions.
You can alternatively purchase a DCS set including a DCS Remote and TIU, and run DCS from that remote.
If you want to just get your feet wet and try out DCS, you could purchase a DCS Explorer for use with any Apple or Android, smartphone or tablet (including a Kindle Fire), and the free DCS App.
Unfortunately, about the only way that you cannot operate DCS is from a Windows smartphone or tablet.
To learn about how to use DCS via the DCS Remote, you could purchase a copy of The DCS Companion 3rd Edition.
To learn about how to use DCS via the DCS App, you could purchase a copy of The DCS WiFi Companion 2nd Edition. This book also has instructions to use the DCS App on a Kindle Fire tablet.
 | Everything that you need to know about DCS is all in MTH’s “The DCS Companion 3rd Edition!" This book is available from many fine OGR advertisers and forum sponsors, or as an eBook or a printed book at MTH's web store! |
 | Everything that you need to know about DCS WiFi is all in MTH’s “The DCS WiFi Companion 2nd Edition!" |
