I am a biochemist/molecular biology PhD student, but I can provide some general advice you may find helpful.
The prior advice you received, to look at specific topics then find labs is good advice but there are pitfalls, I would try a different tack. The problem you can run into is that you may apply to schools under the impression that there are positions available in the labs you identify as interesting. It may not be until you get to the school that you realize this isn't the case. This could happen for any number of reasons, the PI lacks the time, space, money, etc to take a student a particular year. She/he may not even know if positions are availabe as far out as the recruiting period, so positions of interest may or may not be available. I think you have the right to ask and try to ascertain as much information in this regard as possible, especially before moving across the globe, but the PI's themselves don't always know what will happen with current students graduation or the next grant, etc
I believe if one is truly interested in science that there are many problems and projects that would excite and motivate you, within a field such as bioinformatics (or in my case, gene regulation). Identify universities that have multiple faculty in an area of interest. This shows the school has made an investment in this area. As a student, you benefit greatly if this is the case. First, you have multiple options for labs to rotate in and potentially join, which insures you against the pitfalls I mentioned above. Additionally, you will be exposed to questions that may be of interest you couldn't have identified beforehand (i.e. not published yet, new, etc) Also, it enables you to form a thesis committee made up of multiple people who can really impact your science, rather than just one or two experts and a number of people on the outside of your field looking in (such people can be valuable, but real expertise can help you solve problems).
It seems to me that some of the coolest work being done at my university isn't published yet or outlined on a PI's website. Going to a place with multiple faculty working in a given sphere can help you stay ahead of the curve and identify novel problems or solutions to tackle beyond iterating existing work.
Lastly, I see talks all the time from people like me who work at the bench and muddle through data analysis. We don't always have the right answers and approaches at the computer. Likewise, I see talks from computational biologists who have lost sight of, or never saw, aspects of the biology they are trying to analyze. Thus, I think there can be real advantages to joining a department or umbrella program where you gain enough of an understanding of the bench side of things, and interface with bench scientists, to truly understand all facets of the problem. This last piece of advice may not be relevant to all computational biology, but certainly applies to the world of ChIP-seq, RNA-seq, etc, in which I am immersed.
Good luck.
I suggest reading up on what problems are currently associated with bioinformatics (there are a lot to do) and target specific topics you are interested in. Then find labs that work on those topics. Talk to the PIs of these labs about possibly working with them rather than submitting blanket applications to a bunch of schools. Most schools/labs like to see that you've done your research about the field and have at least a general goal of what you want to accomplish.