As for medications to try, go with what my husband suggested, Cialis. Why? Because it's hard to not feel sexual when your clit keeps sending off throbbing sensations when you're least expecting them! I'll take it in the morning and by late afternoon I'm feeling it's effects without even thinking about anything sexual. The sensations will last through the night and into the following day. During sex, it just engorges the clit and makes it feel wonderful and like it MUST be taken care of. The next day I'll be driving or what ever and it's like WHAM...my clit just reminds me it's there and wants some attention. I would imagine if I was a guy I'd have a raging hard-on popping up out of my pants. The only thing that bothered me about cialis was at first I was having some odd dreams and it was difficult to fall asleep, but that doesn't happen anymore. I was taking a whole one, but I've downsized to a half. Mentally, the cialis will help your wife if she's lacking general interest in having sex because her clit will be reminding her it's there and wanting to be played with.
What makes me orgasm really well is more mental than physical. It might be the same way with your wife. Instead of foccusing on what will bring her to orgasm, focus on what turns her on...what gets her juices flowing! Being really turned on will bring on a better orgasm than the best vibe in the world. Take it easy and focus on having fun together, giving each other pleasure, but not necessarilly focussing on the orgasm as a final destination. What used to get her freaky? Think back. What are her biggest turn ons? Is she more into sex at a certain time of the day than others?
I'd also suggest a little slowdown in your attempts at having intercourse and just spend a little more time flirting with her. ( ie. the usual kiss hello or good-bye could be a teasing kiss, press your groin up against her and rub slowly, but that's it, not intending it to lead to more, carress her ass, slide your fingers to her pussy from behind when you kiss her, but that's it...just cop a feel. Fun stuff like that.)
The meds she's on...I don't know about how different ones react, but I know when I was on Zyban (form of Wellbutrin) it didn't affect me negatively. Being depressed will lower her desire to have sex, so good luck to ya both with that part of it.