Welcome!
Don't think that you're too old to swap, sometimes the change is just what is needed!
You didn't mention whether the size of the phone is important, and if so, whether you want to stick to iPhone sizes? Assuming you wouldn't rule out something a little larger, I would suggest a couple of phones, one android and the other a windows phone.
For android, I would suggest waiting for the new Nexus 5, it should be a good phone when it is released - date not yet confirmed. If you want to keep the phone to a similar size to Apple's, then a mid-range Samsung like the S4 mini might meet your needs. I've not used this phone, so can't comment on its pros/cons.
As an alternative, I would also recommend a Windows phone. Having a Lumia 920, I know the call quality is very good and it has free Nokia Drive and Maps built in, which you can download so you won't even need to use your internet allowance. There's also full Word, Excel etc so if you use an office pc, it ought to sync easily. Camera is also of good quality. In regard to size, there are several (almost too many) in the range to choose from, so you should find one that meets your criterion.
Hope these help.