if the system is working fine for you and performing well, then no need to do much of anything...
if you want to improve your current system, just two things... as some said, add more memory and bring it to 4GB... XP will address most of it... and the other one, add an SSD drive...
The SSD investment can be carried over to a new PC when the time comes. Those two things right there will provide you with another year very cost effectively... total cost $150-$200.
now, buying a new PC will certainly improve the performance and overall response of your application, specially TWS.
I promote buying reman... and I prefer HP workstations or their business class desktops... I do not buy consumer computers and I dont promote to "build your own"... people try to nickel and dime at times with technology and I just find that hilarious at times...
http://h71016.www7.hp.com/html/hpremarketing/daily.asp
yes, can go nuts spending thousands on a new computer, but in reality... you will spend $350-$850 for a good computer... and here is an example... middle of the road..
HP z220 W7P-64 i5 3470 3.2GHz 500GB SATA 4GB(2x2GB) DDR3 1333 DVDRW(LS) Intel HD 2500 Rmkt SFF WS $649.00
HP z220 W7P-64 X E3-1225 V2 3.2GHz 250GB SATA 4GB DVDRW(LS) Intel HD P4000 Rmkt SFF WS $679.00