No, H7 bulb does not fit the H4 socket. The most cost effective for your car is buying the very high efficiency plus 50 H4 bulb such as Philips Vision Plus or Sylvania-Osram Silverstar. You can but Philips Vision Plus H4 for $28, shipping included, from England via autolamps-online.com. I bought Philips VP H4 and H7 light bulbs from them about 2 years ago and very happy with the improvement over the OEM. I kept the OEM for spares.
I re-read Sylvania and Osram web pages, I think the Silverstars under two names are the same. But if you are not sure, then stick with Philips Vision Plus or Osram Silverstar, then you are sure to get the bulb with 50% more light than standard one. One thing for sure: do NOT pay big bucks for PIAA.