You can get a DD-WRT compatible router from ebay or aliexpress from $15-$25 including international shipping.
Use the DD-WRT router as a secondary router and connect the DD-WRT router’s WAN port to one of the LAN ports of your main broadband router .
Use the setup instructions that you received with the DD-WRT router and log into the admin interface. First you have to set a LAN address range that doesn’t interfere with your regular LAN address range. Click Save and your router will reboot.
Access your router on the new LAN address and go into the WAN menu. Select PPTP. Please test your network that it doesn’t block PPTP beforehand using our demo account and PC.
For gateway (PPTP server), use one of the server names from your subscription confirmation email.
Set DHCP to yes. This assumes that your original LAN has a working and properly configured DHCP server.
Set the WAN connection mode to automatic. Click Save. Your router may reboot. If your router becomes unresponsive, unpower it and power it back on.