Sorry to hear about your purchase error. But you can play most games using Manual PLP techniques, with any graphics card. I've been doing this for quite awhile now, & have had great success.
But it is more work than Eyefinity PLP & results not always as ideal (e.g. stretched HUD or FMVs, or borderless requirement). Despite this, Manual PLP is a lot of fun to use, looks better than supported LLL (IMO), & is satisfying for a PC tinker (because you take the responsibility of spreading these games with minimal support).
Per-game instructions are posted for Manual PLP here (in no particular order). These instructions are only for games that have been tested.
http://www.wsgf.org/blog/imusrt Here's the guide to help with these instructions (maybe should start here). Also there's help for untested games & piles more info available, if you follow the links on the guide.
http://www.wsgf.org/blog/imusrt/2015/03 ... structions(Wolfenstein The New Order 2014, manual PLP)
As for your R9 290, you will never receive Eyefinity PLP support for it, because the card itself lacks the new modification for mixed-orientation.
R9 300 series is coming out shortly, which will also support Eyefinity PLP. AMD is finally backing PLP \m/.