A few things you might consider is to try running dual surrounds, one for each row. You might try to simulate that by putting both on the same side aligned with each row and see if you can get a feel for how it might sound if you did that on both sides. You could also just order another pair and if it doesn’t work send them back for about $30.00 shipping.
If you can use a ceiling mount to get around the fact there is a window between the seats you could mount them between the rows as John suggested using blinds or curtains to tame any potential harsh reflections off the glass.
Although it wouldn’t help with the surround soundstage you could get a receiver capable of using wide speakers which will help wrap the front soundstage around the front row more and give that row a different sort of ear candy.
Cheers,
Dean
