fitting five car seats in a mini van ... recommendations please?

[mama~bear]

Here's our current set up.  We're adding #5 in June and we have to figure out how to add another seat!

in the rear row with only the tiniest space between the two seats

7yr old - Graco Nautilus

5 yr. old - True Fit

In the captain's seats:

4 yr. old - True Fit

3 yr. old - True Fit (rear facing)

Our plan is to put the newborn in one of the True Fit's and buy two new seats for the 4/5 yr. olds. 

Any recommendations?  We have a Kia Sedona and live in the UK.  We can have seats shipped via Amazon since we have an APO address.

Thanks so much, it's been three years since I researched what's out there and you ladies are so knowledgable!!

[Maedze]

What year is your Sedona, before I answer :-)    Also, we'll need weights and heights of the other children.   

[mama~bear]

2005 Sedona (don't know if it matters but we did buy it here in England

5 yr old (6 next month) 46" and 45 lbs

4 yr old - 42" and 38 lbs

thanks so much!!