Current best bet is using our sun as gravitational lens, but with current technology it would take 2-3 decades to get satellites far enough (few times further than New Horizons is currently) for that to be possible.
Gravitational lensing is one option, but another is the Terrascope concept whereby the Earth's atmosphere would be used as a refractive lens. In theory, any atmosphere would do. It may even be possible to use Jupiter's outer atmosphere. As refraction is stronger than gravitational lensing, such schemes would not require multi-decade trips out focal points at edges of the solar system.