Question about Axle shaft replacement

I have got lots of help here that I highly appreciated. Here again for help.

I have my VW 2000 Passat checked today prior to my 3000-mile long trip. It is found that two front axle shafts need to be replaced. Including an additional tranny fluid change, all together will cost me over $600.

My question is: can I do the replacement after my trip? Is it dangerous to drive the car with axle defect?

Thanks a lot in advance!