Hi Sagar,

You can use the following codes to taking backup and restore sql server 2005 database.

For that you have to add some namespace in your cs file:

Microsoft.SqlServer.management
Microsoft.SqlServer.Management.NotificationServices 
Microsoft.SqlServer.Management.Smo
Microsoft.SqlServer.Management.Smo.Agent
Microsoft.SqlServer.Management.Smo.Broker
Microsoft.SqlServer.Management.Smo.Mail
Microsoft.SqlServer.Management.Smo.RegisteredServers
Microsoft.SqlServer.Management.Smo.Wmi
Microsoft.SqlServer.Management.Trace 

Now you add the following function  for Backup and restore database:

//Code for backup databse
public void BackupDatabase(String databaseName, String userName, String password, String serverName, 
String destinationPath)
{
Backup sqlBackup = new Backup();

sqlBackup.Action = BackupActionType.Database;
sqlBackup.BackupSetDescription = "ArchiveDataBase:" + DateTime.Now.ToShortDateString();
sqlBackup.BackupSetName = "Archive";

sqlBackup.Database = databaseName;

BackupDeviceItem deviceItem = new BackupDeviceItem(destinationPath, DeviceType.File);
ServerConnection connection = new ServerConnection(serverName, userName, password);
Server sqlServer = new Server(connection);

Database db = sqlServer.Databases[databaseName];

sqlBackup.Initialize = true;
sqlBackup.Checksum = true;
sqlBackup.ContinueAfterError = true;

sqlBackup.Devices.Add(deviceItem);
sqlBackup.Incremental = false;

sqlBackup.ExpirationDate = DateTime.Now.AddDays(3);
sqlBackup.LogTruncation = BackupTruncateLogType.Truncate;

sqlBackup.FormatMedia = false;

sqlBackup.SqlBackup(sqlServer);
}

//Code for restoration od database:
public void RestoreDatabase(String databaseName, String filePath, String serverName, 
String userName, String password, String dataFilePath, String logFilePath)
{
Restore sqlRestore = new Restore();

BackupDeviceItem deviceItem = new BackupDeviceItem(filePath, DeviceType.File);
sqlRestore.Devices.Add(deviceItem);
sqlRestore.Database = databaseName;

ServerConnection connection = new ServerConnection(serverName, userName, password);
Server sqlServer = new Server(connection);

Database db = sqlServer.Databases[databaseName];
sqlRestore.Action = RestoreActionType.Database;
String dataFileLocation = dataFilePath + databaseName + ".mdf";
String logFileLocation = logFilePath + databaseName + "_Log.ldf";
db = sqlServer.Databases[databaseName];
RelocateFile rf = new RelocateFile(databaseName, dataFileLocation);

sqlRestore.RelocateFiles.Add(new RelocateFile(databaseName, dataFileLocation));
sqlRestore.RelocateFiles.Add(new RelocateFile(databaseName+"_log", logFileLocation));
sqlRestore.ReplaceDatabase = true;
sqlRestore.Complete += new ServerMessageEventHandler(sqlRestore_Complete);
sqlRestore.PercentCompleteNotification = 10;
sqlRestore.PercentComplete += new PercentCompleteEventHandler(sqlRestore_PercentComplete);

sqlRestore.SqlRestore(sqlServer);

db = sqlServer.Databases[databaseName];

db.SetOnline();

sqlServer.Refresh();
}

Now you have call both function on same event
like, if you want both task done in single click, then you call both function with 
required parameter in button click event.

I hope it will help you.