Putting new seals in your turbo is cheap and easy. Please understand that this is not the same as rebuilding your turbo. To truly rebuild your turbo, you need to take it completely apart, clean everything thoroughly, polish the shaft(lol) and have it balanced again. If you want your turbo to last for years, this is the only way to do it right.
Having said all that. You can probably run it for a while. It will only get worse though, since you are not holding oil pressure where you should, and every time you hit boost, you are wearing the shaft and bearings more and more. Just going around town, your turbo is seeing temps of up to 1200 degrees. When you are in boost, 1600+ degrees. Not to mention that it is spinning at hundreds of thousands of RPMs. You run the risk of getting metal into your oil system, which then feeds right back into your oil pan and can produce spun rod and main bearings. IMHO it is not worth it to run a known bad turbo. Just my $.02, hopefully it helps...also keep in mind I am super conservative with these kinds of things.