I'd keep your a/b. Like anything else, they're aren't getting any cheaper, and arguably just more complicated.
My biggest learning blocks to being adept (well competent anyways) with an airbrush are roughly in this order:
Workspace. It's possible to set up and break down the a/b for each use, but having to unpack it, set it up and arrange whatever else you need all the time will frustrate you. If there's a corner of the garage, basement or patio where it can live, you'll be much happier.
Equipment. Having owned quite a few, I don't make much of a distinction in difficulty of use between single and double action, but a double action brush is certainly preferrable in terms of results. Otherwise it helps to have one that's easy to maintain. Some, like my Patriot, really don't even need to be taken apart to clean them after use, other than to run some solvent through them, and withdraw and wipe the needle. That helps keep the frustration level to a minimum as well.
Paint. While they are popular because of their relatively low amount of fumes, acrylics IMO are the hardest to airbrush. This is just my opinion. They are very sensitive to what they are thinned with. It's not as simple as "add water" for many types. A lot of space in a/b forums seems to be devoted to thinners, ratios, brand compatability. I learned to airbrush with lacquers, and those are great. A good modeling example is Alclad 2. Next simplest for me are enamels like Humbrol, that thin with traditional mineral spirits. I started using acrylics with the Polly Scale line of Floquil paints. Those were water soluble, and easy to clean up.
So, I'd keep your rig, and when the weather turns nice again set it up somewhere where it can stay out under a cover. Spend a little time and money on a variety of paints and see what you like. Economics of buying spray in cans does weigh, and the inclination to buy cheaper spray can paint will bite you back.
Good luck,
Bill