You need to apply for an R-1 visa stamp at the U.S. consulate in your home country. Only when you have that R-1 visa stamp in your passport can you return to the U.S. and continue your R-1 status.
You are confusing the terminology in your question. You do not currently have an R-1 visa. You have an approval notice that shows that an R-1 petition was approved and your nonimmigrant status was changed to R-1, and your current status is valid until April 2013. That status is not a visa. You cannot receive a visa while in the U.S. You can only receive a visa at a U.S. consulate, and these are only located outside the U.S.