You will notice a benefit to upgrading your turntable when you do it, but I suggest getting a DAC right now because you don't seem to have anything except your Dell's audio out jack for playing digital music.
So I say keep the turntable upgrade in mind and start researching it, but spend now on a DAC and cables. Personally I would suggest the SimAudio Moon 100D DAC. It has a USB input which you can use for now. You will have enough cash left over to buy a good USB cable, like the cryo-treated silver one from Audiogoner Acreyes -- look him up.
Later, to upgrade your digital sound, you will want a USB-to-S/PDIF converter (one like the Valab Tera-Link X which sells on eBay for $60), plus a 1.5 meter coaxial interconnect cable.
That's what I would do, and there will be others who have their own favorite approaches to your needs and budget.
So I say keep the turntable upgrade in mind and start researching it, but spend now on a DAC and cables. Personally I would suggest the SimAudio Moon 100D DAC. It has a USB input which you can use for now. You will have enough cash left over to buy a good USB cable, like the cryo-treated silver one from Audiogoner Acreyes -- look him up.
Later, to upgrade your digital sound, you will want a USB-to-S/PDIF converter (one like the Valab Tera-Link X which sells on eBay for $60), plus a 1.5 meter coaxial interconnect cable.
That's what I would do, and there will be others who have their own favorite approaches to your needs and budget.