Gifts are given to make some other person happy. For couples, it can even save a relationship from falling into a rut. If you feel as if she is losing interest, try to get more romantic gifts for her. Those are gifts that can certainly bring back that loving feeling.
You can always give small tokens of affection and cards. To make it more personal, you can always have a personalized card made for her that will say exactly how you feel. Tokens can be something like the Have I Told You Lately That I Love You token which says it all.
If a lot more effort is needed, how about giving an experience gift. You can get a romantic experience gift for two that will let both of you spend some quality time together. Take a cruise along the Thames or have dinner in Paris via the Eurotrain. There are lots of different romantic experience gifts to enjoy.