Well I got a close up filter just to get a taste of it (11 dollars, can't go wrong! ) and if I really like it then I think I'm going to upgrade to extension tubes with contacts or just go all out and get a macro lens! Thanks so much for the comment, it was very helpful!
For macro stuff, I've always used a HOYA Close-Up filter... you can get them at different magnifications - I have the +4 one. I've always been happy with the results it produced.
For a remote, I've always used a Nikon ML L3 (wireless). It's infrared, but I'm not certian if it will work with your D5100. I have D90 which is older than your DSLR. If it will work with yours then I'd highly recommend it. It's just straightforward and easy to use. Comes with a little carrying pouch/holder too.
I found one not long ago that is from a brand called Neweer, and it had a few features I liked, so I went ahead and bought it It will be a while before I get to use it since it's going somewhere else, but I can't wait!