Hi Yogesh,
You can add an HTML area component that contains an iframe that loads a VisualForce page with code that generates the URL for the New action of your custom object.
<iframe style=”background:transparent; border:0; overflow:hidden” src=”/apex/<Name of VisualForce page>” height=”100″ width=”100%”></iframe>
Change <Name of VisualForce page> to the name of the VisualForce page that contains the button:
<apex:page showheader=”false” sidebar=”false” standardstylesheets=”false”>
<apex:form >
<input type=”submit” value=”New”
onclick=”window.top.location='{!URLFOR($Action.<Object API Name>.new)}’; return false;” />
</apex:form>
</apex:page>
Change <Object API Name> to the API name of your custom object.
Note that iframes don’t grow/shrink to fit their content so you’ll have to set an explicit height. The loaded content is actually served from the force.com domain, so cross-domain security stops you accessing the parent document to resize it automatically.
Thanks