How to come to an agreement with a spouse on a future vehicle?

Family of 5 - 3 kids under 10 and adults mid 30s.

Monthly Budget:

• Take home Income 4,672
• Mortgage (1,200) - balance 138k value 190k; 13 years left at 2.875%
• Student Loans (2,000) - balance 45k
• Exterminator (42)
• Power (80)
• Water (32)
• Gas (35)
• Car Insurance (85)
• Vehicle Gas (80)
• Mobile Phones (77)
• Life Insurance (21)
• Internet (75)
• Trash/Sewer (45)
• Food/Grocery Items (800)
• Entertainment (100)
   
  As you can tell, we are being VERY aggressive on the student loans because I'd like these knocked out as soon as possible. The student loan payment usually sits around 2k per month, but is adjusted for surprise expenses (such as a car repair, etc.). Student loan debt is 45k. Food is higher than it could be, so there is some opportunity there.
   
  We currently own two vehicles outright (2003 Elantra; 2008 Elantra) - both have 90k miles on them. The older car is showing it's age a bit, but per the mechanic it seems like it should last a while. My spouse and I are in agreement (she is not thrilled though) that we will try to get through the student loans first before considering a vehicle purchase; maybe 2 years if there aren't any major medical/home repair/car repair surprises. We have 1k in savings (loosely following Dave Ramsey - I still use credit cards/pay them immediately for small rewards). After it's paid off, she would like to spend around 20k on a used Ford Explorer so she has something a bit larger for toting around the kids. I'm not completely opposed to the cost, but I would like something cheaper if possible and I'd really like to avoid a car payment. This means like another year of saving to get a car; possibly longer because we are going to start putting away 15% of our income for retirement after student loans are paid (doing zero right now). Another note is she is in her final year of college (costs are already covered) - and might be making 30k a year starting next June; but this is up for debate if it would be better for her to just continue to stay at home (it's likely she will want to work). Only one kid would need daycare and the other two would need before/after school care depending on schedules.
   
  What say you PF? Creative solutions are encouraged :)