how can i improve my bandwidth is there any tweaking i can do?

You can not improve your bandwidth by tweaking. You can impact the efficiency of your use of the bandwidth with some tweaks.

There is a tweak that can improve your speed.
This will help increase your bandwidth for any network connection in Windows XP PRO.

1. Make sure your logged on as actually "Administrator". do not log on with any account that just has administrator privileges. To log in as an administrator:
-click on start->logoff->logoff
-in the logon screen hold Ctrl+Alt+Del.
-in the user field type 'Administrator' <-case sensitive.
-in the password field type the password for the administrator (if you don't have one leave blank)
-press ok

2. Start - run - type gpedit.msc
3. Expand the "Computer configuration" branch
4. Expand the "Administrative templates" branch
5. Expand the "Network" branch
6. Highlight the "QoS Packet Scheduler" in left window
7. In right window double click the "limit reservable bandwidth" setting
8. On setting tab check the "enabled" item
9. Where it says "Bandwidth limit %" change it to read 0-- Click apply, OK, exit gpedit.msc
10. Go to your Network connections (start->my computer->my network connection-> view network connections). Right click on your connection, choose properties then under the General or the Networking tab (where it lists your protocols) make sure QoS packet scheduler is enabled.
11. Reboot , now you are all done.

This is more of a "counter what XP does" thing. In other words, XP seems to want to reserve 20% of the bandwidth for itself even with QoS disabled. So why not use it to your advantage? To demonstrate the problem, start up a big download from a server with an FTP client. Try to find a server that doesn't max out your bandwidth. In this case you want a slow to medium speed server to demonstrate this. Let it run for a couple of minutes to get stable. The start up another download from the same server with another instance of your FTP client. You will notice that the available bandwidth is now being fought over and one of the clients download will be very slow or both will slow down when they should both be using the available bandwidth. Using this "tweak" both clients will have a fair share of the bandwidth and will not fight over the bandwidth.

no nada nothing

Your connection speed (upload/download) is set by the ISP; there isn't much you can do about it unless you pay.