Definitely not. A Duron 1.3GHz is strong competition for the 1.7GHz Celeron, as is your present processor. Any gains would be very minimal, and is some areas you'd lose performance.
Granted the Celeron 1.7GHz overclocks decently, but even highly overclocked it still only manages XP1600+ performance.
If you want a cheap upgrade just by an AXP 1600+/1700+/1800+, that way you won't have to replace your motherboard and you get stock performance that is easily far better then the stock 1.7GHz Celeron.... the lower end AXP's o/c nicely also.