R22 is a fairly environmentally damaging refrigerant from both a ozone layer and global warming potential (GWP) point of view- if the leak keeps recurring band-aiding it with frequent top-offs may be cost-effect from an out of pocket point of view for a short-termer, but replacing the unit with something that maintains it's hermetic seal is highly encouraged.
In some countries it's legal to replace R22 with propane, and several R22 replacements out there are based on propane. But the oils typically used in R22 systems are miscible in liquid propane, so it's sort of like putting 5W oil in an engine designed for 20W- it won't crap out instantly, but it's not best practice. The flammability of propane has kept it from being a legal replacement in much of the first-world, even though propane is orders of magnitude more benign to the environment than R22 or R410A. In a hermetically sealed system it's not particularly dangerous, but I don't need to point out that yours has some leakage issues...
R410A is far better refrigerant than R22 from the ozone point of view, but it too is an extremely potent greenhouse gas, and is
likely to be phased out sometime in the next decade. Already HFC134a (the most common automotive AC refrigerant) was banned in EC, as of 1 January this year, and Honeywell is pushing their HFO-1234yf as a comparable but extremely low GWP refrigerant. Many of the European auto makers have settled on CO2 as the standard automotive AC refrigerant though, despite the extremely high operating pressures that require more expensive compressor technology. It's hard to predict at this point what will become the R410A replacement for the residential AC market, but if you're out & out replacing the R22 based system, it might be worth looking into it a bit closer, even if R410A is still the dominant refrigerant, lest you be looking at yet another orphaned-refrigerant system 15 years hence.
Hopefully the brazing job will hold up, and you get another decade or so of service out of it.