1994 Nissan Altima - as you can see you've bought a car that is half if the market value. It has two names, either Nissan Bluebird SSS or Nissan Altima. It wasn't a really popular model back when it was new and I don't know why since it has a pretty trick engine the SR20, the same engine is also in the older Nissan Serena Highwaystar 2.0 and Nissan Silvia S15 (the top spec comes with the SR20DET which is a turbo version of the engine). Yeah, so engine wise it is pretty sweet. The gearbox is nothing special, good enough and reliable. You should send the car for a check up as I remember replacing bushings for this car cost a bomb anywhere between 1000-2000, aircon kaput would be around 1500, mostly this two issues. But it surely can vroom vroom on the highway 120kmh is nothing

Probably due to age as the SR20 was designed to be quite frugal but of course considering 90's tech a frugal engine was anything that return >350km per tank of fuel which seems barbaric nowadays with Hybrids, Skyactiv and Diesel engines returning anywhere between 400-800km per tank of fuel.

Maybe when funds are available you can consider a top half overhaul to clean up the carbon and sludge build up over the years, going for those gimmicky carbon cleaning services that runs gas through the engine isn't going to help an engine that has done 200,000kms 

A Hyundai Atos would be worth anywhere between 5k-10k, you can do this to increase your value. Sell the Hyundai Atos to used car dealer A. Then go to used car dealer B and buy something like a 2013 Perodua Viva 850cc Manual you may have to top-up or you may not have to. However, I highly doubt any used car dealer would agree to do a swap since you're giving them an older and lousier car for the same price 

Once this is done you have a car which would cost you RM420 to insure yearly and RM20 for roadtax. Typical service for such a car every 5000km can be as low as RM50 for the usual engine oil and filter. Aircon service can be done at minimum twice a year. Using a washable steel mesh airfilter further saves cost as you don't need to replace it when it is worn. So moderate usage and upkeep would cost you under RM700 a year which is like RM2 a day which is quite cheap.

I don't know what kind of job you do but if you're office bound you can use the Viva for your work commute and appointments then have the Altima as a nice weekend car. You can keep the Altima at home for your parents/housewife to use to do the daily chores, mileage won't be high for such activities thus preserving the mileage on the low side which in turn lowers your fuel cost.

Or theoretically you can trade-in two cars to a used car dealer for (estimate) rm10k each then choose a car which is around the 20k range maybe something like this 2012 Proton Persona 1.6 auto which isn't a bad car since it is C-segment and bigger than your Atos but after enjoying the Altima's SR20 to a Proton Campro S4PH (i'm sorry proton fanbois) the feeling is like getting kicked out of Pavillion and into Sg. Wang Plaza. But it might be a more economical choice if you want better fuel consumption and just maintaining one car.