Hi.
I hope for further cooperation.
At this time I cannot configure Microtik as OpenVPN server, need create certificate, etc.
But can help with aggregate your two connection, configure Mikrotik as OpenVPN client (you will must provide root and client certificates and key from OpenVPN server, also Mikrotik not support UDP mode, LZO compression, TLS authentication, authentication without username/password, server must configure via TCP), can configure Mikrotik as PPTP servet for VPN connection, etc.
Not need for prepaid. If hire to me work, will pay after finish.
Pls. provide information about your time zone and convenient for you working period.
My spoken English is not very good, so, if possible, we will communicate via correspondence (or chat).
Thanks.