Has anyone had wifi issues with iPad 2 after the 6.1.3 update ? Will it go away on its own? Apple wants me to send it in for replacement but if it would start working properly I want to keep it.

I have had wifi issues with my iPad 2 since I updated my iPad. Can it resolve on its own? I am still under warranty, but I would like to keep it if its possible that it could resolve, apple told me to send it in for replacement, I have reset my router, reset my network setting ,restored my iPad to new iPad nothing is working, I was tethering off my phone but that has stopped working as well, I was losing wifi every five to ten seconds now I have it for twenty minutes to an hour at a time. Please tell me what you think I should do anyone.