Rather than a decision, I'll offer you a decision process. It's work, but it will help you make a better decision. I reccommend something like this as a sticky, because this question appears often.
1) Cruise craigslist to identify a couple likely replacement cars by year/model. Beware cars selling for much cheaper than their value on kbb.com - probably due to issues not mentioned in the ad.
2) Gather all your receipts for repairs, insurance, maintenance, and stuff. Factor in gasoline and estimate depreciation (not including the latest mechanical issues). Estimate an average cost per year to have your car.
3) Go to
www.edmunds.com/tco.html and submit a query for your alternative car. Note that 2011 is as far back as it goes.
3)(a). If you would replace your car with a pre-2011 model, you can rough-estimate the costliness based on the cost curve from 2011-2013.
For example, the total cost to own a 2011 Outback for the next 5 years is $29,196 (
https://www.edmunds.com/subaru/outback/2011/st-101323979/cost-to-own/). A 2013 model costs $33,578. From the $4,382 difference across 2 years, we can guestimate you'll save $2,000 for each year older you buy. So a 2010 Outback will cost 27k/5y, a 2009 will cost 25k/5y, and the curve probably starts to flatten from there as repairs become a bigger expense than depreciation and the cost of insurance and property tax hit their respective floors.
So what's cheaper? Trading up, or fixing up your existing car? Now you have all the tools you need to decide.