worth upgrading

hi
at the moment my current system is a socket A amd sempron 2200+ with 746mb pc3200 ram. i am going to upgrade to dual core when both the new chips have come out from amd and intel but was wondering would i get a good speed increase if i upgrade to a:
amd opteron 144
http://www.overclockers.co.uk/show [...] subcat=640
motherboard:
http://cgi.ebay.co.uk/ws/eBayISAPI [...] &rd=1&rd=1
i can use the ram from my old computer and if i buy a pcie video card now ill be able to use it when i upgrade to dual core. everything else like harddrive,case and pse i already have.
all this should cost about £60 and would come handy when i upgrade as a server or a pc for my little brother

for £60 will it be a good upgrade for speed compared to my sempron as then i could hold off a dual/quad core upgrade till beginning of 2008 where hopefully more programs willtake advantage of it and ill have a bit more money then. at now i have about £120 and aint got a job yet as im 15.
also whats better that opteron or a 3700+ oem