The required time for repairing a damaged radar varies and depends upon the extension of possible damages.
In the recent sabotage, small suicide drones were launched at radar sites of Iranian IADS network. If we suppose that antenna along with the complex electronic parts of different radar systems were damaged, it will take 2 to 3 weeks to fully repair and diagnose them in emergency conditions.
Cost is an important factor in this field but it doesn't really matter when the country is at war. My guesstimate is that at least 1 billion dollar has to be spent on locally developed radar sites from long to medium range ones. Foreign radars including Russian radars such as Nebo, if ever damaged in the internal sabotage will cost a lot. Not to mention the availability of the damaged parts which have Russian origins.
Last year a huge amount of electronic components were imported into the country via a 3rd country. I don't think that we gonna have problem in the availability factor. Mostly imported from Europe and East Asian countries, they were of high quality products. It meets at least 10 years of Iran's needs. At least I am not worried about that issue.
So if the government raises funds, it will take only a few weeks to fully repair, diagnose and operationalize the damaged radar sites/systems.