what is more important cpu or gpu in gaming?

Looking at the specs of your present computer I would vote for the graphic card. The celeron is not great but on-board graphics are probably even worse. Therefore the graphic card most likely would give you the best boost...

However :

1. Are you sure that your motherboard can handle a GT440 ? You need a PCI-e 2.x 16x Interface for it !

2. If the answer to question 1 is no and you decide to buy an I3, are you sure that it will fit on your motherboard ?

neither...if you are going to upgrade, upgrade both because if you get an i3 the motherboard will not be compatible with it...cpu socket is wrong..if you get a gt440...the cpu u have at the moment will be bottlenecking it...but i will answer your question....the gpu is slightly more important then the cpu in gaming...reason is that if you rely on intergrated graphics on your cpu...it has its important job already...that is 2 do all the calculations and display it to the user. On the other hand thats why the gpu comes in handy because it gives the cpu an easier job because the gpu is specialised in bringing up displays with performance and quality...bottom line is...save up more, upgrade motherboard, cpu and gpu and ram beacuse the newer motherboards will need some ddr3 @ 1333 frequency ram

nicely what's important in a solid GPU is the memory Clock , Shader Clock , engine clock , pixel fee , Pixel shader v 3.0 or bigger and vertex shader 2.0 or extra suited . in case you do no longer waht to spend plenty funds , you shud decide for the nvidia 9800 GT 512 MB . dont decide for a million gb because it supplies precisely comparable overall performance as a 512 mb .

gpu must 512mb and cpu core 2due or higher for gaming best for i3 processor u need to upgrade motherboard