Hi Nadia,
I totally understand your dilemma, as I have been through it similarly before.
I also don't speak French but if you apply there, you need to fill out forms for course equivalency. They will take this into account when they look at your application and award you the credits if they match. The thing is that you need to expect LOTS of paperwork to make sure this goes through. For my Master's program, they didn't accept any of my bachelors credits for Master's equivalents but I know someone who has been in your exact situation and was able to get bachelors classes credited. It's worth a shot, just make sure you have lots of paper evidence.
Where are you currently going to school? What is their policy on transfer credits? What program are you trying to get in to specifically at UNIGE? They have different requirements.
The other thing is that each program at UNIGE has a different level of required French, so you should check your program's website for info on what level they require. You will need to take some sort of French exam to be permitted to enroll if your program is in French. My program is entirely in English and even requires TOEFL for those who don't come from an Anglophone undergrad, and I STILL had to take a French exam. So, you have two choices: either take the university one, or take one with your chosen French school, which will probably be easier.
In terms of French schools, the best/inexpensive one is by far that I've seen are the ones at UNIGE's language faculty (http://www.unige.ch/lettres/elcf/index.html). There is also !Fage (www.ifage.ch), which might have something more intensive.
I hope this helps. Feel free to PM me if you have any more questions about UNIGE and the language barrier :)