  While observations of many high-precision radio pulsars of order
$\lesssim1~\mu$s across the sky are needed for the detection and
characterization of a stochastic background of low-frequency gravitational
waves (GWs), sensitivity to single sources of GWs requires even higher timing
precision. The Argentine Institute of Radio Astronomy (IAR; Instituto Argentino
de Radioastronom\'ia) has begun observations of the brightest-known millisecond
pulsar, J0437$-$4715. Even though the two antennas are smaller than other
single-dish telescopes previously used for pulsar timing array (PTA) science,
the IAR's capability to monitor this pulsar daily coupled with the pulsar's
brightness allows for high-precision pulse arrival-time measurements. While
upgrades of the facility are currently underway, we show that modest
improvements beyond current plans will provide IAR with unparalleled
sensitivity to this pulsar. The most stringent upper limits on single GW
sources come from the North American Nanohertz Observatory for Gravitational
Waves (NANOGrav). Observations of PSR J0437$-$4715 will provide a significant
sensitivity increase in NANOGrav's "blind spot" in the sky where fewer pulsars
are currently being observed. With state-of-the-art instrumentation installed,
we estimate the array's sensitivity will improve by a factor of $\approx$2-4
over 10 years for 20% of the sky with the inclusion of this pulsar as compared
to a static version of the PTA used in NANOGrav's most recent limits. More
modest instrumentation result in factors of $\approx$1.4-3. We identify four
other candidate pulsars as suitable for inclusion in PTA efforts. International
PTA efforts will also benefit from inclusion of these data given the potential
achievable sensitivity.
